I have one DNN instalaltion with 8 parent portals.

In 7 portals I can set the timezone , no problem.
In one portal the time zone I select is not saved. it jumps back to the original setting after updating it.

Also in the tab "user account setting" I can cretae a custom registration form, but when i save is it jumps back to the "standard" registration form.
In the other portals I do not have this behaviour.

Probably I did something wring in this portal but cannot figure out what.

I would be great if somebody could help me.

Have you checked the event log for any errors related to this?

No, unforunately i did not check the event logs.

Since the site was only 5 pages I created a new one.
In the new portal I change the timezone without any problem.

Thanks for your help.

In the new site the problem pops up after activating multilanguage pack.
I already read about the poblems with multilanguage pack does exist in the version I use ( 7.3.2)

Should I upgrade to 7.3.4 or is it better to wait a little longer?

I don't see any issues upgrading from 7.3.2 to 7.3.4.