IMAP Server Timeout: Complete Troubleshooting Guide [2025]
Most of the email clients’ users face a common error, and that is the IMAP server timeout, whether you are using Outlook, Thunderbird, Apple Mail, or mobile apps. Usually, it happens when the email app takes way too long to connect with the mail server.
This timeout only interrupts your workflow, but also delays important messages from syncing. In this article, I will walk you through what are the causes behind it, how to fix it, and how to avoid it from recurring.
Table of Contents
What Is an IMAP Connection Timeout?
IMAP stands for Internet Message Access Protocol. It helps you to access emails stored on the server from multiple devices. When any email client gets impatient as it waits too long for a response from the server, then the issue happens. If the communication gets delayed or blocked, the email app pops up an error like:
- Server not responding
- Connection to server timed out
- IMAP Authentication Failed
Common Reasons for IMAP Server Timeout
Here are some reasons why this error appears:
#1. Slow or Unstable Network Connection
Make sure your network connection is stable and you have a good internet speed, as it can cause a timeout.
#2. Large Mailbox or Folders
Sometimes, the syncing of a large mailbox or folders that have thousands of messages causes the IMAP connection timeout.
#3. Incorrect IMAP Settings
The connection fails or is delayed because of a wrong port number, security type, or IMAP server.
#4. Antivirus or Firewall Restrictions
If you have an antivirus, then disable it for some time, as it can stop the connection between the client and the server.
#5. Server-Side Outage
Sometimes the issue is on the email client end; contact them and ask them if there is an outage or if they are under maintenance.
#6. Add-ons or Extensions
Add-ons or extensions can play a major role in causing the error if they have access to controlling syncing.
#7. Heavy Attachments or Too Many Sync Tasks
IMAP connection timeout happens when your mail app takes too long to sync because the messages are too large or too many devices are connected at the same time.
Related article: IMAP Folder is Not Properly Syncing
Easy Steps to Fix a Connection Timeout Issue
When you face an IMAP server timeout, follow the below quick steps below to resolve the issue:
#1. Make sure you have an Internet Connection
Make sure your internet is stable, and it is working on other devices. You can check it by opening any browser or using any speed test app.
#2. Raise the IMAP Connection Limit
Most of the email clients give you the privilege to extend the timeout limit so the server gets more time to respond.
Take Outlook as an Example:
- Go to File> Options
- Open Advanced
- Under Send/Receive, click Send/Receive
- Select the IMAP account and click Edit
- Increase the server timeout slider
#3. Verify IMAP Settings to Avoid IMAP Server Timeout
Make sure:
- IMAP server name
- Port 993 with SSL/TLS, or
- Port 143 with STARTTLS
#4. Reduce your Inbox Size
When your mailbox becomes too large:
- Always archive old emails
- Delete your junk or unnecessary folders
- Move big attachments out of the mailbox
#5. Temporarily Disable Antivirus or Firewall
Disable your security tools for some time to check if they are causing the issue. Also, add your email app and ports to the firewall’s exception list.
#6. Remove and Re-add the Email Account to Avoid the IMAP Server Timeout
Most of the time, resetting the entire syncing settings fixes corrupted cache or outdated settings. So, remove IMAP account and re-add it to fix this problem instantly.
How to Ensure Data Continuity While Addressing Timeout Issues
After following all the above steps, the errors go away, but come back, and it happens to multiple users. In this case, you must consider using a reliable tool, which is SysTools IMAP Backup Software, as a part of your routine. It will help you to download a clean and secure copy of all your IMAP emails.
You can archive IMAP emails, compact the mailbox size, and keep your IMAP account hassle-free, which results in reducing the load during syncing and preventing timeout issues. The most helpful thing is that this tool supports all formats like PST, MBOX, EML, PDF, and MSG.
How to Prevent IMAP Timeouts in the Future
Here are some habits you should follow to avoid frequent timeout errors:
- Regularly clean and organise your email folders.
- Avoid storing large attachments inside IMAP mailboxes
- Keep your email client updated
- Make sure the security software doesn’t block ports like 993 or 143
- Reduce the frequency of automatic syncs if you don’t need constant updates
- Always keep fewer devices connected to the same IMAP account
These are some small adjustments you need to follow smooth connection between your email client and the server.
Author’s Verdict
IMAP server timeout errors can be annoying if you are a working professional and your workflow depends on email for work. The good news is that after knowing the causes and following the steps as shared above, you can get rid of this IMAP connection timeout problem. Check all the antivirus and settings, a stable connection, and a well-maintained mailbox. Contact your mail server to check if there is any outage from their end.
People also ask:
Q. Is it possible that a server outage causes an IMAP timeout?
Yes, if there is an outage from your server’s end, then the IMAP timeout
Q. Can I face an IMAP server timeout on multiple devices?
Yes, it is possible if you do too many simultaneous syncs
Q. Can removing and re-adding the email account resolve the issue?
Yes, the issue gets resolved as it resets the settings and fixes timeout errors.
Q. Is a large inbox file a reason for IMAP connection timeout?
Yes, a large inbox file can be a reason for an IMAP timeout by slowing down syncing.