Unable to start Postfix in Plesk: /usr/sbin/postconf: libmysqlclient.so.18: cannot open shared object file: No such file or directory

Symptoms

• Domain creation fails in Plesk:

  PLESK_ERROR: Nothing of nonexisting mail features are not supported

• Postfix doesn't work with the following error:

  CONFIG_TEXT: /usr/sbin/postconf: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory

• The plesk repair mail command execution ends with an error:

  # plesk repair mail
  Repairing the mail server configuration
  Reconfigure all domains and mailboxes? [Y/n]
  Reconfiguring all domains and mailboxes .........................
  ERR [util_exec] proc_close() failed
  ['/usr/local/psa/admin/bin/mchk'] with exit code [1]
  [FAILED]
  - mchk failed: ==> Checking for: mailsrv_conf_init... fail
  Error messages: 0; Warnings: 0; Errors resolved: 0
  exit status 1

• The postfix check command shows the following error:

  # postfix check
  postfix: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory

• The libmysqlclient.so.18 package cannot be found:

  # rpm -qf /usr/lib64/mysql/libmysqlclient.so.18
  error: file /usr/lib64/mysql/libmysqlclient.so.18: No such file or directory

Cause

The libmysqlclient.so.18 package is missing on the server (which can happen due to the MySQL upgrade).

Resolution

1. Connect to the server via SSH

2. Install the missing package:

# yum install mysqlclient18-compat --enablerepo=mysqclient

3. Update package version for Plesk:

# plesk sbin packagemng -sdf