Internal server error message

The issue you are facing: I get an error message when I try to access my NC Dashboard from desktop or mobile, or run any of the NC apps on my phone, see below error message from desktop. NC is running on a hosted VPS. I have no or limited admin knowledge, so not sure where to start with debugging this (or how to find out version of Ubuntu, Apache etc.). I am able to access the server via sftp and ssh.
Any suggestions for where to start?

"Internal Server Error

The server encountered an internal error and was unable to complete your request.
Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
More details can be found in the server log."

What was the last thing you’ve been trying to do?
Do you know if there is any program running on your server that is depending to NC, that is not working properly?

And can you also send your log?

Last thing I was trying to do was access some files via my NC android app. There is no other program running that depends on NC.

As per my original post . I do not know much about Linux/admin … Which logs and where do I find them?