Registering problem on osmo-bts

Dear guys, anyone can help me, Im using osmo-gsm-tester osmo-bts.cfg and openbsc.cfg also/ BTS is up and auth policy accept-all is set and even I add subscriber IMSI, but my phone still cannot register on the network. my setup is LimeSDR and using the latest osmo-bts and openbsc with OpenUSRP. do you think its a hardware issue? please help! Thanks -- best regards, DUO