I hosted Mailcow at home, I have two public IPs, in the Mailcow IP I use to host Mailcow behind a router. My Mailcow has two, domain setup for mail, but mainly use one.
I use Fairemail client on Android, and Thunderbird on PC in my home network, sometime if both of them start will it will cause time out message from this … IP (back to normal after a while). If I like to access my webmail from a domain at that time, webpage will not work, but my 2nd domain name works normally from the same IP.
Sometimes the same situation occurs when using mobile data outside the house too, how to solve it?
Is something to do with Fail2ban or DNS?
Any help would be appreciated, I am relatively new to this