You are reporting two, maybe three, different issues.
First, the “Kiss-o-Death” messages are unrelated to any PVoutput issues. IoTaWatt queries a time server every hour, and the time server pool being used in the current release sometimes rejects such a request if it feels you are pestering them with excessive requests (“rate”). These are not causing any problem in the logs you posted. Subsequent requests succeeded. The next release will use Google time services which don’t seem to care how often you ask and I believe have greater local presence globally.
Second, PVoutput has a limit on the number of transactions you can do each hour. You get a lot more when you donate a few bucks, but the free service is fine for ordinary operation. When IoTaWatt gets a response that the limit is reached, it pauses until the next period when the quota is restored. In your case, you have set PVoutput to upload history beginning on 5/24, and so it does that each time it restarts, forcing you to exceed the transaction limit. So on 6/10 it took three hours to upload that history, pausing shortly into each hour as the transaction limit was exceeded. If you clear the upload history date in the PVoutput service, that should stop.
The third problem is the “Fatal response” from PVoutput. I think this is because 5/24 exceeds the lookback period for uploading live data for non-donator mode. I’ll look into that, but I think if you remove the upload history date as suggested in the issue above, that will go away.
You may exceed the transaction limit on restart as it tries to continue from wherever it left off, but if you are patient, it should catch up and work fine going forward.