Hello,
1.
How did you create iptables rules? Through Plesk panel or manually by changing iptables?
Are you sure there is nothing in crontab or other scheduled tasks that can reset iptables in the system?
Take a look at syslog to figure out what causes this behavior.
2.
If you can't find why...
Hello,
1) To clear all data, you can try cleaning up all tables in plesk database, related to WordPress:
| WordpressInstanceProperties |
| WordpressInstances |
| WordpressInstancesDomains |
(!) Do not forget to create database backup, preliminary!
2) The tool to manage WordPress named...
Hello,
Are you sure you have a necessary entries in the hosts file at the requestor's machine?
Something like: xx.xx.xx.xx - webmail.domain.com, where xx.xx.. - your Plesk IP
Try to execute 'ping' command to your webmail. What is the response?