By looking at the timeline and behaviour,
It seems that while there is a network issue in the backend, the records actually does get stored in the table XtkFileRes and upon clicking OK, the process retries the request and at this point the unique violation constraints is triggered as the record did get stored in the first place.
After closing all these error messages, can you actually see the record for which the file is erroring out in the list? because it should exist as that is what the error is mentioning. and is the file actually accessible? are you able to navigate to the backendserver and see the file exist in that path, and is the file accessible from the web browser?
Start by checking the apache logs and the web logs, perhaps run the web server in verbose mode also.
The TraceFilter mode, which lets you save the greatest number of logs. It is activated by the following command:
nlserver stop <MODULE_NAME>; nlserver <MODULE_NAME> -verbose -tracefilter:*
https://experienceleague.adobe.com/docs/campaign-classic/using/monitoring-campaign-classic/troublesh...