Did you reset it by the Reset button on the back or Restored to Factory Default from the WebGUI ? And then configured it from scratch instead of restoring backed-up configuration from file ?

The last thing you can do to confirm the issue is to reset the router and configure it from scratch - then test again.

@FernandoZago If the router settings are persistent and the only change you do to make it work is changing FW version - that sounds like a FW issue to me.

@FernandoZago Did you try to observe the following setting while you were with the newer FW ? System Tools =>System Parameters Then on the bottom of the screen you should have this: You can try to...

Have you tried to reset the router - you got nothing to lose - reset procedure - method 1

TBH it would be a guessing from my side, but I would bet on - too many connect requests send from the router to the provider side (PADI). Immediately after PADI, router sends to provider side...