SM registered but can't registered

Hello Forum,
I have been having some problem with some SM’s in my network. The problem is they are well registered but the client can’t navigate, i had tried rebooting both SM and AP but still no way. I have also disabled NAT to see if that is the problem. I have no idea why it is so or is it an IP address problem?
I dont know what the problem is or what causes it to act like that way, please i will like your ever useful solutions.
Blink 26