in the past days I have delays of around 6 seconds caused by GTI lookups done by the AV engine. If you like you can try those off and see if the problem goes away. We were not yet able to find out what exactly caused those problems.
If you watch our for DNS packets in your tcpdumps, do you see DNS is working quick and reliable, or do you see any instances of delayed responses here?
We do have a couple of debug logs but those will cause a ton of data to be written to the disk. I would recommend to first try disabling some of the cloud lookups to rule out what exactly causes the delays. If we know what goes wrong we can turn on the piece of logging that will catch the required debug details and see what is going on exactly.
whatever that was, meanwhile it seems to be sorted out. I do no longer see delays, performance problems or "server failed".