IMAP not working can’t connect to 143 is a common error that many email users are experiencing when handling the mail server.

This error can occur if the firewall blocks the port 143 or when imapd is not running on the server.

At Bobcares, we often get requests from our customers to fix IMAP not working, can’t connect to 143 error as part of our Server Management Services.

Today, let’s get into the details on how our Support Engineers to fix IMAP not working can’t connect to 143 error.

How we fixed IMAP not working can’t connect error

At Bobcares, where we have more than a decade of expertise in managing servers, we see many customers face problems while managing the IMAP server.

Now, let’s see the major reasons for this IMAP related errors and how our Support Engineers fix the top errors.

In DirectAdmin

After cPanel, another popular control panel is DirectAdmin. It helps to manage the Linux server via a web browser.

Also, many users are using IMAP protocol for accessing email on a remote web server from a local client. Unfortunately, many customers may experience errors like cannot IMAP / Connect on port 143.

Often, in the Directadmin server, this error can occur due to various reasons. It includes,

1. When /usr/sbin/imapd is not executable.
2. xinetd is not running
3. Firewall settings

1. imapd was not executable

Here, imapd was not executable. Then, our Support Engineers did the following steps to solve the error.

rm -f /usr/sbin/imapd
cd /usr/local/directadmin/scripts
./imapd.sh

After that, we test it out as below.

telnet localhost 143
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
* OK [CAPABILITY IMAP4REV1 LOGIN-REFERRALS STARTTLS AUTH=LOGIN]
localhost IMAP4rev1 2003.339 at Thu, 05 Nov 2019 12:39:55 -0600 (MDT)

This solved the problem.

2. xinetd is not running

Sometimes, if the xinetd is not running properly on the server, the cannot IMAP / Connect on port 143.error can occur. a xinetd is an open-source super-server daemon that runs on many Unix-like system. It helps to manage Internet-based connectivity.

In order to check whether the xinetd is running or not, we are using the following commands.

ps -ax | grep inetd | grep -v grep

If it not installed, we install it by using the below commands.

yum -y install xinetd
/sbin/service xinetd start
/sbin/chkconfig xinetd on

In addition, incorrect settings on the server block the working of xinetd. So, we make that the xinetd has the proper settings.

For RedHat, the configuration file is located in /etc/xinetd.d/imap and /etc/inetd.conf file for FreeBSD.

3. Firewall restrictions

Similarly, sometimes the firewall on the server may block the port for IMAP. Many customers complaints that they can connect via localhost and not from outside the server. This occurs when the firewall blocks the port for IMAP.

So, our Support Engineers tweak the firewall setting as open the port for IMAP.

Missing localhost entry

Recently, one of our customers had a problem with the IMAP server. He couldn’t collect mail via IMAP. Because his mail client had failed to connect to the server.

Whenever he tried to telnet to port 143, it did not accept connections on port 143.

Then, our Support Engineers logged to the server and run ‘telnet localhost 143′. Then we got the following output.

telnet localhost 143 Trying xx.xx.x..x.... telnet: Unable to connect to remote host: Connection timed out

Therefore, we checked the file /etc/hosts. An entry was missing.

We added a line to /etc/hosts and solved the error

127.0.0.1 localhost.localdomain localhost

That’s it.

[Need assistance to fix IMAP errors? We’ll help you.]

Conclusion

In short, IMAP not working can’t connect to 143 error can occur if the firewall blocks the port 143 or when imapd is not running on the server. Today, we saw how our Support Engineers fixed this error.