[CentOS] Strange problem with web-based apps

Hello,

I'm not sure if this is a DNS problem as it has just recently started happening or at least I just recently noticed it was happening. This only happens outside my local network. I can only describe the problem.

I use OpenWebmail for webmail. I can read mail, delete mail but cannont send mail. I uses webmin, most this I can admin remotely from this, some I cannot such as the File Manager. I use OSCommerce. Some things I can do from the admin panel, some things I cannot such as update inventory.

When the problem occurs, I get the error in the browser "Cannot Find Server".

Again, this only happens from outside my local network and it only affects some actions.

Any ideas?

TIA

Eddie