How to set up a proxy in Multilogin: add it, check it, fix the errors

To add a proxy in Multilogin, open the browser profile, go to the Proxy tab and choose Custom. Pick HTTP for port 8080 or SOCKS5 for port 1080, paste the line as host:port:username:password in Proxy details and wait for Proxy check passed. Give every profile its own sticky session. Below: each step, every proxy type and a fix for each error.

Multilogin keeps every browser profile apart: its own cookies, its own fingerprint and its own proxy. The proxy decides which IP address and which country the sites see, and Multilogin then matches the profile's time zone and WebRTC address to it. This guide follows the current Multilogin app, the one first released as Multilogin X, in its web interface; the steps are the same in the desktop app. Field names come from Multilogin's own help center, values from the QuanticData endpoint generator.

What you need before you start

• Multilogin with an account. The desktop app, or the web interface with the agent connected: the profile list shows Agent connected at the bottom when it is.
• A proxy plan. Residential Premium, ISP or mobile: each works in Multilogin, and the sections further down say which one fits which profile.
• The line to paste. In the QuanticData dashboard it is under My proxies, on the plan's page, in the Endpoint generator: host, port, username and password in one line.

The proxy format Multilogin accepts

Multilogin takes a custom proxy as one line in Proxy details and the protocol from three buttons above it: HTTP, HTTPS and SOCKS5. Its help center lists two layouts:

• ip:port:username:password for a proxy with a login. A hostname works in place of the IP, and the generator's output format host:port:user:pass is exactly this layout.
• ip:port for an IP-authenticated proxy, where the provider recognises your IP and no login is sent.

The same QuanticData proxy, for each protocol:

# Protocol: HTTP
residentialpremium.quantumproxies.io:8080:USER-country-br-sid-p01-ttl-60m:PASS

# Protocol: SOCKS5, same login on its own port
residentialpremium.quantumproxies.io:1080:USER-country-br-sid-p01-ttl-60m:PASS

Paste the line without an http:// or socks5:// prefix: the protocol comes from the buttons. Choose HTTP, not HTTPS. HTTPS in that list means an encrypted connection to the proxy itself, which these ports do not use; HTTPS websites load normally through an HTTP proxy. The username is the whole string after the host and port: -country-br picks the exit country, -sid-p01 names the session and -ttl-60m keeps it for 60 minutes. Copy it whole.

Step by step: add a proxy to a Multilogin profile

1. Generate the line. In the QuanticData dashboard open My proxies, then your plan. In the Endpoint generator choose the Country (and a Region or City if the profile needs one), set Session to Sticky, set Session TTL (minutes) to at least the time the profile stays open, choose the Protocol and keep the Output format on host:port:user:pass. Copy the line from Preview.
2. Create the profile in Multilogin. Go to Profiles, Browser, and click Create. On the General tab give it a name you will recognise, for example BR profile 01. To change an existing profile, open it for editing instead: the tabs are the same.
3. Open the Proxy tab and choose Custom. Custom is the option for a proxy you bring. Template applies proxy settings you saved before; None uses your own connection.
4. Pick the protocol that matches the port. HTTP for port 8080, SOCKS5 for port 1080.
5. Paste the line in Proxy details. One line, no spaces, nothing after the password.
6. Read the check. Multilogin tests the proxy as soon as the line is in. Proxy check passed means it connected and read the IP data; See details opens the result. Proxy check failed means it could not connect: the fixes are further down.
7. Leave the Fingerprint defaults. With Timezone and WebRTC on Masked, Multilogin takes the profile's time zone from the proxy location and shows the proxy's address over WebRTC. Traffic saver is optional: it blocks images and videos, which cuts the traffic a profile uses, and some sites look broken without them.
8. Click Create, then Start. The profile opens in its own browser window, leaving from the proxy.

That check, run through a Residential Premium line for Brazil on 23 October 2026, came out in Várzea Grande, Mato Grosso, with the time zone America/Cuiaba rather than São Paulo's. Brazil has more than one time zone, which is exactly why Timezone should stay on Masked: a time zone typed by hand would not match the exit.

Check the proxy from the profiles list

A proxy that worked last week can stop working, and Multilogin's own advice is to check it before starting the profile. There are two ways, both from the profiles list:

• Check proxy in the top menu. Select the profile with its checkbox and click the magnifier in the toolbar.
• The right-click menu. Right-click the profile and open Proxies: Check proxy (Cmd+Opt+C on a Mac) tests it and shows a notification with the status, the IP and the location; Edit proxy opens a pop-up to change the proxy without opening the whole profile; Copy proxy copies it as hostname:port:username:password, the same layout as the generator.

One sticky session per profile

An antidetect profile is meant to look like one person on one connection. A rotating proxy changes IP on every request, which suits scraping and breaks a profile that logs in. A sticky session keeps one IP for as long as the session lives, and the session lives in the username, so the line never has to change once it is saved in the profile.

# profile 1: Brazil, one session for a working day
residentialpremium.quantumproxies.io:8080:USER-country-br-sid-p01-ttl-480m:PASS

# profile 2: same plan, its own session (never reuse p01)
residentialpremium.quantumproxies.io:8080:USER-country-br-sid-p02-ttl-480m:PASS

# profile 3: Brazil, open all day
residentialpremium.quantumproxies.io:8080:USER-country-br-sid-p03-ttl-1440m:PASS

Three rules cover almost every case:

• A different session ID in every profile. Two profiles on the same line share one IP, which is exactly what an antidetect browser is there to avoid.
• A lifetime longer than the work. The generator accepts up to 1440 minutes, a full day. When the session ends, the next request gets a new IP, and a site can see that as a new login location.
• The country in the username. Without -country- the exit can be anywhere, and the profile's time zone follows it there.

With Session set to Sticky, the generator makes as many lines as the Quantity field says, ten by default, each with its own session ID; Copy all or Download takes them out in the same format. One line per profile.

Residential Premium, ISP and mobile proxies in Multilogin

Residential Premium

The setup above. One sticky line per profile, with the country, and a region, city or ISP if the profile needs one, in the username. Authentication is username and password; HTTP on 8080, SOCKS5 on 1080. It is the right choice for most profiles: home IPs in the country you pick. More on why each profile needs its own address in residential proxies for antidetect browsers.

ISP

ISP plans list fixed IPs under Assigned IPs, in the format IP:Port:Username:Password, which is Multilogin's ip:port:username:password as it is: paste the line in Proxy details with the matching protocol. Give each profile one IP and keep it: the address does not change, which is what long-lived accounts need. The plans are on the page for ISP proxies.

Mobile

Mobile lines go in the same way: one line per profile, a gateway (Global, USA, EU or Asia), HTTP on 8080 or SOCKS5 on 1080 and a sticky session in the username:

mobile.quantumproxies.io:8080:USER-country-br-type-mobile-sid-p03-ttl-60m:PASS

Mobile plans also offer IP whitelist authentication: add your IP in the dashboard, then paste a host:port line from the whitelist list, which is Multilogin's IP-authenticated format with no login. More in mobile proxies for Multilogin.

Proxy type	In Multilogin	Good for
Residential Premium	Custom, one sticky line per profile; country, region, city or ISP in the username; HTTP 8080 or SOCKS5 1080	Most profiles: home IPs in the country you choose
ISP	Custom, a fixed IP from Assigned IPs as IP:Port:Username:Password; one IP per profile	Long-lived accounts that should keep the same address for months
Mobile	Custom, one sticky line per profile with -type-mobile; Global, USA, EU or Asia gateway; HTTP 8080 or SOCKS5 1080; IP whitelist available	Phone-first platforms and accounts tied to mobile networks
Datacenter	The same one-line format	Testing and low-risk profiles where speed matters more than the type of IP

The plans themselves are on the page for QuanticData residential proxies. If you also run Dolphin Anty, see the same setup in Dolphin Anty.

Adding proxies to many profiles at once

1. Make the lines. In the generator, set Session to Sticky and the quantity you need, generate, then Copy all or Download.
2. Save each line as a proxy template. On Pro 20 plans and higher, Proxy templates in the left menu stores proxy settings: Create, a name such as BR profile 04, Custom, One proxy, the protocol and the line, Check proxy, then Create. A plan can hold as many templates as it holds profiles, so one template per line works.
3. Assign them. Select a template, click Manage assigned profiles, pick its profile and Confirm; or, in a profile's Proxy tab, choose Template and select it. Keep one template per profile: a template assigned to several profiles gives them all the same IP.

For short tests, Quick in the profiles list creates up to 25 temporary profiles at once. With Custom and the Format set to Proxy list it takes up to 25 lines and hands them out Sequentially or Randomly. Quick profiles are deleted, with their data, when you close them, so keep them for tests and use regular profiles for accounts.

A new IP without a new profile

With a custom proxy the IP changes when the line changes. On Residential Premium and Mobile the IP is tied to the session ID in the username, so a line with a new session ID, for example -sid-p02 instead of -sid-p01, is a new IP: right-click the profile, Proxies, Edit proxy, paste it and save. The old line keeps working until its lifetime ends. ISP proxies are static addresses by design: one IP per profile, for months.

Multilogin proxy check failed: errors and fixes

Multilogin reports a broken proxy in four ways: Proxy check failed under Proxy details, a Proxy connection failed notification ("Check if it's online and its details are correct in the profile settings"), Wrong proxy data when the profile starts, or ERR_SOCKS_CONNECTION_FAILED inside the profile's browser. These are the causes behind them, in the order to check.

What you see	Usual cause	Fix
Proxy check failed, or Proxy connection failed	The protocol does not match the port: SOCKS5 on 8080 or HTTP on 1080	HTTP with 8080, SOCKS5 with 1080
The same, with the right protocol	HTTPS chosen instead of HTTP, the username cut, a colon missing or a space in the paste	HTTP, then copy the line again from the generator's Preview and paste it whole
Wrong proxy data	The plan expired or its traffic is used up, or the line is not in ip:port:username:password	Check the plan in My proxies: status, remaining traffic, expiry date; paste the line in the documented layout
ERR_SOCKS_CONNECTION_FAILED in the profile	SOCKS5 set up wrong, usually on the HTTP port	SOCKS5 with port 1080, or switch the profile to HTTP and the port to 8080
Wrong country or time zone	No -country- in the username, or Timezone set to Custom or Real	Generate the line with a country; keep Timezone on Masked
The IP changes in the middle of a session	The session lifetime ended, or two profiles share one session ID	A longer -ttl- and a different -sid- in every profile
The proxy works outside Multilogin, fails inside	An antivirus, firewall, VPN or another proxy tool on the computer, or a system clock set by hand	Pause those apps or add Multilogin to their allow list; set the time and time zone automatically

One test outside the browser settles most cases in a minute. If this returns an address in the right country, the proxy works and the problem is in the profile's fields or on the computer:

curl -x http://residentialpremium.quantumproxies.io:8080 \
  -U "USER-country-br-sid-test-ttl-10m:PASS" https://ipinfo.io/json

If the same command fails on your network but works from another one, your network or your internet provider is blocking the connection to the proxy port. Multilogin's help center suggests the same test: a different Wi-Fi or a phone hotspot.

HTTP or SOCKS5 in Multilogin

Both work for browsing, and every QuanticData network offers both. HTTP on port 8080 is the simpler choice and the one to start with; Multilogin's own fix for ERR_SOCKS_CONNECTION_FAILED is to switch to HTTP, which with QuanticData means port 8080. SOCKS5 on port 1080 passes any kind of connection, not only web pages; the details are on the page for SOCKS5 proxies. What breaks a profile is never the choice itself, only a protocol that does not match its port.

Before you run accounts

A proxy changes where a profile's traffic comes from, not what the profile is allowed to do. Keep to each platform's terms and to the law where you work, and use one profile, one session and one identity per account.