eMails don't work anymore

[ArthurDent]

Hi!

We're working with Plesk 7.5.4. ... some hours ago our Admin tried to update to 8.0 - but "something" went wrong and now the eMail-Accounts don't work anymore.

I've tried to add new accounts, which worked fine. But when sending an eMail to the new one, it is bounced ... when trying to send an email via the smtp, I'll receive an error "mail-server may be down or misconfigured".

I suppose, it's a firewall restriction - but I have no idea where ro look for it. Can you please help?

Thanks and kind regards,
Chris