Did you try to create ftp user from. ISPConfig >> Web access >> FTP accounts
If the emails sent from website form then its difficult to find if its man or spambot. However you can check the access logs of that website and...
What error you are getting while uploading the files? are you able to connect to FTP server?
Look at the solution like R1soft backup, which could be helpful for you.
Looking at error it appears you are sending email to some invalid receipent which is rejected by server.
hmm that makes sense. Did you try to update default DNS template which is under server templates?
Can you confirm the nameservers are pointing for such domain to right server? As I remember you supposed to use external DNS?
Port knocking is a stealth method to externally openports that, by default, the firewall keeps closed. Depends on the setup, how exactly you are...
It should be within apache configuration. Did you check that?
Yes, exactly. The connection is broken or the table is missing the users when he reconfigured services.
Its not about connection is secure or not.. The pure-ftpd is unable to recognize the users for authentication..
If you create any new FTP user, then you see same issue?
Are you sure your subdomain is pointing correctly to your server? Its getting timed out, that suggest some DNS issue..
Horde is just piece of webmail application there wont be such difference by disabling it.
Can you confirm if you are not going to use EXim email...
For top level performance, make sure you have good hardware resources as well as network.
With software thing,optimize apache, use php-fpm...
Separate names with a comma.