Horde webmail interface facilitates easy access of emails from anywhere. All you need is a web browser and internet.

That’s why website owners always prefer webmail for their email accounts.

But, it can sometimes throw weird errors. And, one such error in Horde is “error connecting to mail server“.

At Bobcares, we help website owners solve such errors as part of our Server Support Services for web hosts.

Today, we’ll discuss the top 3 reasons for this error and how we fix them.

What is “Error connecting to mail server” in Horde?

Horde is one of the commonly used Mail User Agents. In other words, this is an interface where users interact to view and send emails.

When a user sends an email, the Horde webmail client transfers it to the sending mail server. After that, the recipient mail server accepts the mail and store it in the inbox. Finally, the recipient webmail client contacts recipient mail server and retrieves the new email.

But sometimes, Horde webmail client can’t communicate with the mail server and leads to “error connecting to mail server“.

Our Support Experts primarily check the Horde logs to determine the source of the problem. In Plesk, the Horde log location is /usr/local/psa-horde/psa-horde.log.

For instance, a complete error message looks like this:

ERR: HORDE [horde] FAILED LOGIN for test@domain.com (test@domain.it) [201.1.114.21 to Horde [pid 154628 on line 211 of "/usr/share/psa-horde/login.php"]154628

“Error connecting to mail server” in Horde – Causes and Fixes

Let’s now see the common reasons for this error and how our Support Engineers fix them.

1) Firewall restrictions

Software firewalls such as iptables, CSF, and intrusion prevention software can sometimes block access to some IPs or IP ranges based on abnormal behavior. Similarly, server firewall sometimes blocks connections to mail ports.

So, if the firewall doesn’t allow connection, users see “error connecting to mail server” in Horde.

How we fix?

Firstly, our Support Engineers check whether the user’s IP address is blocked in the server firewall. If blocked, we remove the firewall block and restore the webmail access immediately. After that, we identify the reason for the block and inform the customer.

In addition to that, we use the telnet command to check that the email ports are opened on the server. For example, see the below command.

telnet domain.com 25

If we find any connectivity problems, we ensure that email ports such as 25, 587, 110, 143, 993 are open on the server.

[Is firewall blocking your connection? Click here to get one of our Support Experts to look into your issue.]

2) Service downtime in the server

Similarly, users see this error when they access Horde webmail using IMAP connection. Users get locked out of the Horde webmail even though they give correct credentials.

This is because the IMAP service isn’t  active or running in the server. Therefore, it can’t process the requests from webmail.

Likewise, we’ve seen instances like server owners install MailEnable on Windows servers, but it doesn’t support IMAP connection. In these cases, customers receive “error connecting to mail server” in Horde.

How we fix?

Our Hosting Experts check whether IMAP service (courier-imap or dovecot) is enabled and active on the server. For example, we use the below command to verify the same.

netstat -tulpn | grep :143

Additionally, we check if we are able to connect to the IMAP server using the below command.

telnet localhost 143

If the IMAP service is stopped, we restart the service and restore Horde access immediately. For example, in Plesk servers we start the IMAP service from Plesk > Tools&Settings > Services Management.

Likewise, if we find that IMAP isn’t supported by MailEnable, our Support Engineers install a MailEnable version that supports IMAP. If that’s not possible, we suggest customers to access Horde using POP3.

[Trouble starting IMAP service on the server?  No worries, one of our Server Admins can help you here.]

3) DNS errors

To authenticate, webmail client connects to the mail server remotely. If the DNS records of the mail server can’t be resolved properly from the server, users will not be able to login to Horde webmail.

Consequently, users see ‘error connecting to mail server’ in Horde webmail client.

Similarly, missing localhost entries in /etc/hosts file and duplicate entries in /etc/nsswitch.conf may also lead to this error.

How we fix?

In such cases, our Support Engineers ensure that proper DNS records exist for the mail server. As a temporary workaround, we add the mail server entry in the /etc/hosts file.

Similarly, we’ll cross check the /etc/hosts and /etc/nsswitch.conf files and ensure that valid entries are there.

Conclusion

In short “error connecting to mail server” in Horde can happen due to IMAP service downtime, firewall restrictions, and more. Today, we’ve discussed the top 3 reasons for this error and how our Server Support Engineers fix them.