Proton Mail Bridge Not Working? 10 Proven Fixes

You may have encountered a problem where your Bridge does not connect, fails to sync new emails, does not launch, stops running, or no longer functions with your desktop email clients. This is a fairly common Proton Mail Bridge error and is usually the result of improper settings or an authentication, network or out-of-date software issue. If the Proton Mail Bridge not working, users might stop receiving/sending messages all of a sudden from their desktop email application, such as MS Outlook or Mozilla Thunderbird. 

Here, in this blog, we will be explaining 10 efficient trouble-fixing ways to get rid of this problem, along with the mention of a professional backup tool for safeguarding your mail messages before attempting any such major troubleshooting steps to prevent harm first and foremost.

What is Proton Mail Bridge?

Proton Mail Bridge is a desktop application that lets you securely connect your account with other traditional email clients like Microsoft Outlook, Apple Mail, Thunderbird, etc. Instead of connecting directly to the Proton Mail server, the email clients mentioned here connect to the bridge using the standard IMAP and SMTP protocols. It encrypts and decrypts the emails locally, while allowing the use of Proton Mail with a desktop mail application.

As the Bridge is the middle layer between the Proton Mail and the email client, any issues with this could cause an interruption in the email synchronisation, receiving messages, and sending.

Before Fixing, It Is Best to Backup Proton Mail Data

Before carrying out any major fixing steps, it is strongly encouraged right away to form a backup of your Proton Mail email data, first of all. Problems uncalled for during such fixing could, at times, result in data loss or missed mail messages. The Proton Mail Backup Wizard helps people to safely backup your Proton Mail messages to multiple formats, including PDF, PST, MBOX, EML, etc.

This utility tends to preserve properties, email attachments, folder hierarchy, & metadata at the time of moving or exporting data. It even supports various selective backup options, which makes it simpler to store just those emails saved before doing any alterations to any of the Bridge settings.

Common Reasons Why Proton Mail Bridge Not Working

There is nothing so strong to disturb your work productivity so quickly as checking your inbox and finding that messages have stopped syncing for many hours. Multiple factors could cause the Proton Mail Bridge not to connect, as follows:

• VPN conflicts: Problems could be happening due to VPN software. Modern VPN apps have the feature of blocking ads and/or malware. Proton VPN also has such a feature, which could be the cause. 
• Antivirus restrictions: Antivirus & security software could be the culprit here. Such a connection issue could be due to the antivirus or other such security software on your device. 
• Device & Network firewall blocks: Firewalls could even lead to such an issue where the Bridge does not work properly, because it needs a connection to Proton servers. It is recommended to add an exception for Bridge in your Firewall.
• ISP restrictions & Geoblocking Issues: Unluckily, ISPs or even countries could block the connection to these Proton servers. In such scenarios, users won’t be able to connect from their devices with that particular internet connection. 
• Outdated Bridge Version: Proton frequently updates server-side protocols, and an old Bridge can lose compatibility
• Some other reasons: 
  • Wrong IMAP/SMTP settings
  • Authentication failures
  • Corrupted cache files
  • Unsupported Linux password managers

Before Anything, Update and Fully Restart the Bridge

This method usually solves any issues with Proton Mail that is suddenly stopped working:

1. Open Bridge, check settings for any pending updates, and install them.
2. Now, fully exit the Bridge from the system tray/menu bar.
3. Relaunch Bridge and allow it a minute to reconnect and resync before starting the troubleshooting.

Check out other related articles | How to Fix Proton Mail Storage Quota Exceeded?

10 Proven Ways to Resolve the “Proton Mail Bridge Not Working”

Safety must not come at the price of accessibility! Luckily, most such Proton Mail Bridge problems could be fixed very easily using the following methods:

1. Re-authenticating the Bridge Account

A common resolution for such a Proton Mail Bridge login error seen suddenly is to re-add your account. Try removing your account from both the email client and the Bridge. After this, you can configure your account once again from scratch.

2. Force Manual Resync

If you encounter the Proton Mail Bridge not syncing issue, forcing manual resynchronisation might help.

To do that, Manual Resync:

1. Open Proton Mail Bridge.
2. Enable Split Address Mode.
3. Wait for a few minutes.
4. Disable Split Address Mode again.

Mostly toggling these settings refreshes the sync process and restores the missing emails.

3. Verify Local Ports & IP Settings

Incorrect local settings could lead to a Proton Mail Bridge authentication or connection error message.

Make sure that

1. The email client is using Bridge-generated IMAP & SMTP credentials generated by Proton Mail Bridge, rather than the normal Proton password.
2. Email Client is connecting to localhost (127.0.0.1).
3. Ports configured in the email client match those provided by Proton Mail Bridge.

Verifying these settings would resolve the authentication and connectivity issues with the Proton Mail Bridge.

4. Disable Antivirus and/or Add Exceptions to Proton Mail Bridge

Some Antivirus programs might block Proton Mail Bridge by mistake, as it handles encrypted email traffic.

1. Add the following locations to the allow-list of your antivirus:
   • C:\Program Files\Proton AG\Proton Mail Bridge\proton-bridge.exe
   • %AppData%\Roaming\protonmail\bridge-v3\updates
2. Allow-listing both folders assists in avoiding such Proton Mail Bridge SMTP error cases.

5. Allow Bridge via Windows Firewall

Is your firewall somehow blocking your Proton Mail Bridge? A firewall might stop Bridge from contacting the Proton servers, leading to such a Proton Mail Bridge IMAP error. To allow proper access, you can carry out the following steps:

• Open the Start Menu.
• Search Allow an app through Windows Firewall.
• Select Change Settings.
• Select Allow another app and browse to proton-bridge.exe.
• Enable access for the appropriate network type.
• Save the changes and restart Proton Mail Bridge.

6. Check Corporate Network Firewall Restrictions

Home networks seldom block Bridge; however, office networks usually do this. If you are working on a corporate network, then you can tell your IT team to allow the following:

• Domain: mail-api.proton.me
• Ports: 80 and 443
• IP range: 185.70.40.0/22

After the connections are permitted, restart the Proton Mail Bridge, and check whether the issue is resolved or not.

7. Temporarily Disable VPN & Alternative Routing

Is the VPN leading to Proton Bridge not working in your case? Modern VPN tools, along with malware/ad-blocking features, tend to interfere with Bridge. Firstly, you must disable Alternative Routing from:

1. Open Proton Mail Bridge.
2. Go to Settings > Advanced Settings.
3. Disable Alternative Routing.
4. Disconnect the VPN temporarily.
5. Restart Proton Mail Bridge and check that it is connecting successfully.

After doing this, turn off the VPN temporarily and then restart the Bridge.

8. Enable Alternative Routing for ISP Restrictions

Some ISPs or certain regions might block access to Proton servers, resulting in a Proton Mail Bridge no internet connection error message. If you aren’t using a VPN already, then follow the steps given below

• Open your Bridge Settings.
• Navigate to Advanced Settings.
• Enable Alternative Routing.

If such a method fails in your case, then you must connect via Proton VPN or try switching to another network.

9. Try to Raise Server Timeout & Sync Frequency

Various email programs disconnect if somehow encrypted connections respond very slowly. You can attempt to do the following changes:

• Increase your server timeout settings in Mozilla Thunderbird or any similar email program.
• You can configure send/receive intervals for checking messages each minute.

10. Try Clearing Bridge Cache & Also Check Linux Password Manager

Any corrupted cache file can prevent the Proton Mail Bridge from syncing properly.

To clear the local cache:

1. Open Proton Mail Bridge
2. Go to Settings > Advanced.
3. Click Clear Local Cache.
4. Restart the application.

Clearing cached data usually resolves such stubborn syncing issues.

Linux users must also make sure that a supported password manager like Secret Service or Pass has been installed, as Bridge largely relies on these for safely saving credentials.

FAQs

Q) How to resolve the Proton Mail Bridge authentication failed error?

A) You must remove the account from Bridge and, after that, from your email program, and then configure your account again by making use of Bridge-generated credentials this time.

Q) Why is Proton Mail Bridge not synchronising messages in MS Outlook?

A) Outlook syncing problems mostly happen due to corrupted account settings, firewall restrictions, and/or stuck large emails. Re-adding your IMAP account usually fixes the issue readily.

Q) Why is Proton Mail Bridge not connecting to the email program?

A) This mostly occurs due to firewall restrictions, wrong login details, VPN conflicts, or even outdated Bridge settings.

Q) How to resolve Proton Mail Bridge sync issues?

A) You can try re-authenticating your email account, clearing the Bridge cache, disabling antivirus for the time being, or even forcing a manual resync if nothing helps.

Conclusion

The Proton Mail Bridge not working issue could lead to missed crucial communication. Luckily, most such issues could be taken care of by following the aforementioned 10 proven fixes. After all, a secure email system is considered efficient only when each email reaches its destination exactly when it is required!