Server instability?

[CologneSky2]

Hi,

just noticed that the server seems to crash quite often recently. Anyone else noticing this as well?
Anyhow, after crash typically the server does not fill up properly anymore (well if the crash is after 10pm).
Tonight for instance, server crashed at around 11pm and now it is virtually dead with only 10 players..

Any ideas/solutions what/how this is caused and how to fix it?

Cheers
D