I have used this in the past and has worked perfectly but now my FritzBox 7490 won't save DynDNS information. After entering correct account information and clicking submit, information stays there but if I navigate to some other screen and come back to DynDNS page it's blank. I have tried other providers as well with no luck. Anyone else had similar experience or can advise what is going on here?  I reset my router after the recent OS upgrade as I wanted to clear everything and now this won't work. 

It did work fine until I reset it.
If I restore to an older backup then I can see the dynu information saved in there and it works but if I attempt to change to a different provider or turn it off, keeps reverting back to dynu settings.