Messages with punctuation in Subject Line: Page Not Found

Why can I not access OWA messages that have punctuation in the subject line?

On the Exchange server running OWA, server/exchange/username works fine and I can log into any account without authenticating and read all messages. If I use the IP address I can only read messages WITHOUT punctuation and I have to authenticate.

Inside the network on a workstation computer, sometimes I can login using server/exchange/username and sometimes I get Page Not Found. Log in using IP address and I can read only messages without puntuation in the subject line.

I’m looping and need clear perspective from someone!