Unable to start Postfix in Plesk: /usr/sbin/postconf: libmysqlclient.so.18:

[senthil]

Symptoms

• On a RHEL-based Linux server, domain creation in Plesk fails with an error that is similar to the following:
  Nothing of nonexisting mail features are not supported
• Postfix cannot start due to an error that is similar to the following:
  
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  /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 that is similar to the following:
  
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  #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:
  
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  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:
  
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  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 sometimes happen due to a
MySQL/MariaDB version upgrade).

Resolution
1. Connect to the server via SSH

2. Install the missing package manually:

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#yum install mysqlclient18-compat --enablerepo=mysqclient
3. Update the package version for Plesk:

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#plesk sbin packagemng -sdf