PPPOE breaks after 24h of running UCS, URGEND

Hello,

a mysterios thing happend.

I installed an UCS with Kopano in a vmware virtual maschine. Since the last wednesday this running system let the pppoe connection crash.

I tested the following:
changed the router (DrayTek 2862), changed the router manufacturer (AVM Fritzbox), nothing helped. If we connect the server, the internet connection failed. If we cut the server, the internet connection come back again.

Changed the switches, nothing helped.
stopping the vm with ucs, the PPPoe is stabel

  • i installed a complete new vm with ucs, install kopano and imported the backup.
    – 24h later, the PPPoe connection cracks, shutting down the ucs: internetconnection is all right.

  • i updated the Vmware to the latest version, doesn’t help

  • i installed the ucs on a NUC, the systems runs 24h, after that, PPPoe failure, no internet.

i don’t have any ideas now, what it could be.

The routers still have sync with the dsl dslam.

Does anyone has an idea?