The mod dynamx is broken by this the mod dynamx is safe in itself but it seems to be blocked

Do you have logs or anything showing how its broken ?

log just unfortunately not I would have to look

but to understand what the error is you need to know what DynamX does

DynamX is a vehicle mod with realistic physics
the problem now is that when you install packs for the mod there is a way to protect them and then the last data is downloaded when you start the game
and this process no longer works and crashes

If it crashes it should generate a crash report. Would you be able to send that ?

I also just created an instance to test this myself with DynamX & SerializationIsBad on the latest forge version and had no issues. Even when i added a content pack

ok this is very weird but thanks for the quick reply

yes in version 3.3 this works in version 4.0.0 it does not load the content packages and then it stays in this screen

here the log latest.log
info this time there was no crash but it does not load the protected models

That issue has nothing to do with SerializationIsBad. Your issue seems to be that you are unable to reach the download website for the mods addons. I would suggest making an issue with the mod maker of DynamX or asking in their discord.

I'm in contact with the developers they say it's SerializationIsBad because the mod somehow blocks something

I tried it without the mod and it worked without problems

and the creators say it's not their mod but SerializationIsBad

The mod wont change anything unless its specified in the config. And when it does patch something it announces it in the log. I didnt see a patch announced in your log from SerializationIsBad i was also able to run the mod, the basic addon pack and Serializationisbad myself with 0 issues