In the system logs of the SSLV a line like the following can be found when trying to download a diagnostics file:
x_archive_add() failed:X_ARCHIVE [0x000000d380090013;code:19;sub:211] Archive library error
This issue can be caused by a network issue between the client machine and the SSLV or a resource issue (CPU too high).
It is necessary to determine whether it’s caused by CPU usage or a network problem and address it appropriately in order to be able to download the diagnostics file without issues.