Hello @Wolfmann, please refrain from spamming your own post as it won’t get us to answer it any faster, as we don’t monitor the forums outside of office hours.
Is your console connected through cable?
Were you able to play the game without issues before?
Does it happen in any server?
Can you try powering off and disconnecting any other devices that make use of the router, both wired and wireless, so that only the console is connected to it through cable?
Does the Router provides logs to give further insight on the crash / error?
Can you also check if it’s possible to limit the bandwidth for the XBOX through the router settings?