Hi All The problem I am having is a couple of users in the same location are having issues collecting their email on their mobile devices. The issue appears to happen when they are connecting from certain providers (roaming, I can tell from the IP in the log) and for pop3 at least shows as pop3d: LOGIN FAILED in mail.log. So to sumarise from certain IPs it works from others I get login failed. We had assumed they were being hit by port blocking as changing this had fixed issues on the SMTP side but again it is very hit and miss depending on their roaming and then finding the pop3 login failed would appear to show the port is fine and something else is causing the issue. Further debug ifo is needed. Is there anyway I can debug this further with courier? My setup is an email server built using the perfect server guide with courier and debian wheezy (I had to improvise slightly as the latest guide for courier was on squeeze). It is running ISPconfig 126.96.36.199 and everything is up to date, or at least it was two weeks ago.