Just to make sure all of the basics are occurring as expected:
Does M587 report the expected network?
Did you delete existing networks with M588 S"*", then re-enter your expected network using M587 S“mynetwork” P”mynetworkpassword” (making sure that the case of each is correct)? Note that attempts to overwrite the network setting with M587 doesn't seem to work unless you delete the old one first - but it sounds like you did.
When you enter M552 S1, the blue led should flash for a few seconds as it tries to connect. Then you should get a message back either saying that it is connected successfully with the IP address it obtained from DHCP reported, or you should get back a message saying that it failed to connect. Are you getting either message?