Seems to be an issue around prime time (17/18GMT+1 to ~22GMT+1). I personally have had the issue for months, solely related to servers hosted at the same provider as the official C-RPG ones, this includes a teamspeak server, everything else is fine. It used to be just Sundays for me, then suddenly pretty much every evening, ups and downs though.
There's still a lack of conclusive evidence, if you want to help get more to do the Ping Plotter in
this thread. Much too few at the moment to build a proper map.
The more routes and pings we can plan out the better and more clearly the issue can be pinpointed.
As it stands now though, as far as I personally can see and have investigated, the issue is with the hosting provider.
I know that some providers throttle UDP traffic to save bandwidth and that might be the case, that's just my personal opnion though, there's no proof of such here so far.