I have configured flowroute SIP credentials in my Android and I am able to make calls outside but not able to receive incoming calls.
When I contacted Flowroute support, they informed send me below email and request you to suggest how can I resolve this issue.
"I traced some call logs and see the calls hitting your device, however they are going to port 64528 which is not supported. Please make sure that you have port 5060 opened up. We only support port 5060 and 5160.
You should have some SIP options to select port number. Unfortunately Flowroute cannot assist with detailed device configuartion setup."