Server Error! (Internal Server Error)

[ericx]

On roughly 60 second intervals, there is a 3 second red pop-up error message which reads:

Server Error! (Internal Server Error)

This alarming message is unaccompanied by any messages in the php error_log. Mail appears to work. I can send and receive. I can create sieve filters with ManageSieve. However, this is a new install and I'm the only one poking at it.

How do I find out what's wrong?

[SKaero]

Is your logs directory wirable?

[ericx]

Sorry. I had switch back to SquirrelMail. RoundCube is pretty, but the customer gets billed by the hour...