Initial Step for Tracking an Unknown Enterprise Portal Issue

If you are having an issue on Enterprise Portal for Dynamics AX 2012 with no warning/error messages and wonder how you can start tracking this issue, here is the place that you can find the log files for SharePoint.

C:\Program Files\Common Files\Microsoft Shared\web server extensions\$VERSION\LOGS 

In addition, you can also check the event logs on the SharePoint Server which you can locate at

Server manager | Diagnostic | Event viewer. 

Right Click on Application and do Save All Events As 

to save the log file.