If your having issues receiving calls on Asterisk based PBX's version 1.6 and higher, please see below for a possible solution to this issue:
Please check your sipgate-peer "type" setting. If this is set to "peer", your Asterisk will not accept incoming calls over this peer anymore, but will reject the calls with "401 Unauthorized" message.
Please adjust this setting to use "type=friend", incoming calls should then be accepted again.
Important: As always we recommend using "sip set debug" and "core set verbose 10" on your console as a troubleshoot, through which a diagnosis and workaround is usually possible.