Always happy to be of help @sultan.mohd2023 
In future, I would definitely recommend the Post route vs a DM though, as it means others will be able to assist, and also everyone gets to benefit from the answer 
By all means feel free to add a specific mention to the post, but if the person mentioned specifically isn’t available for whatever reason it should mean you’ll get to a resolution in a timely fashion 
And about that Auth0 custom extensibility thing, can you tell me how can I check this and make sure that everything is disabled correctly
The best way to do this is to follow the Auth0 Docs by using each of the (extensibility) links I shared previously; there isn’t once central location for disabling all Auth0 extensibility, unfortunately. I’d also double-check that you don’t have any Auth0 Extensions enabled either (which might be causing an issue).