could be.
You need to contact your host to be sure.
BTW, Since your host says it only happened after years of service. Makes me suspect.
Hosts are constantly upgrading software versions(apache,linux,windows), adding security,etc.
So I am sure it is something they did and now you need to fix it.
Ubb does not send email from nobody it sends it from the email account listed n the UBB control panel.
So something is amiss with the account entered.
Being that the php.ini is using the wrong mail connection. Or you need to manually enter a new SMTP server location.
