Roon, Expert Pro, and a major issue with RAAT

[K4680]

Hello, slowly I think that everything is possible.
A friend called me on the weekend that he suddenly had problems (1 year without problems) with Roon RAAT.
He described the following errors: Runs normally for some time, then charging problems and stuttering, HiRes Flacs stuttering or not charging.  Since we are not far away I said to him take your devialet and the nucleus and come to me.  We wired everything up and started with HiRes Flacs, no problems.  Everything we tested ran normally, after 3 hours we stopped the test.  What can cause the error?  I then suspected his network / router, so I packed my router (FB 6591) and a switch and we drove to his home.  I now connected the switch and router to the devialet and the nucleus, and lo and behold, the same error as before with his devices, now also occurred with my devicesäten.  After a long debate, he suddenly said that he had asked his Internet provider to increase the bandwidth from 200 M / bit to 500 M / bit !!  Are there timing problems with the ISP distribution points, or more workloads in the segments (500 M/Bit)? Everything else in the network telephone, TV, Internet, mail without problems.
Maybe that's why some of us have no problems with RAAT!
At the moment at a loss!

Short info: The ISP reacted quickly and was the first to notice significant differences in the ping times.  From 40 msec.  up to 750 msec. !!  The search continues

Addendum, RAAT interference on the 1GB cable connection!
ISP reacted promptly and fixed the problem.
Error:
1. Shielding on a cable from the house connection amplifier, almost torn off.
2. Transfer amplifier defective, delivered too high level.
3. New house connection amplifier installed, level set exactly (ping time 35 ms)
4. According to the technician, a segment amplifier was faulty in a distribution station!

After 2 days Roon-RAAT with Devialet runs without any problems !!!

Apparently, this time Devialet are not the bad guys!