Hello
I am developing an IOS client SIP client based on linphone-iphone (Phone iOS 3.12.1 and Core 3.9.1). Well.. developing is a big statement since I am just customizing the linphone-iphone source a bit to meet my needs. Downloaded the source files and compiled them for use on regular devices (../prepare.py && make). The code compiles just fine and runs on an IPAD with IOS9.2. Outgoing calls work fine and incoming calls as well when the app is in the foreground. As I noted in the mailing list that receiving calls in the background only works when TCP transport is used, I tried switching to TCP in the settings, but after having done so, the app will not register anymore. it fails registration with an "unkown error" dialog.
At first I suspected my service provider, but they support TCP. To verify that this is indeed the case I ran linphone downloaded form the google play store on an android device and this device registers just fine over TCP with the same provider. even TLS registration worked.
Then I checked if the problem might be related with the sources I downloaded , so I installed the official app store version of linphone on the same IPAD and tried registering on the IPAD (IOS 9.2) over TCP. The official version has the same problem. It refuses to register over TCP (only UDP works) and the same "unknown error" feedback appears.
Strangely the problem can not be reproduced when I run the code from either the i386 nor the x86_64 simulators in Xcode; they all register just fine using TCP.
Has anyone experienced a similar issue on IOS 9.2? Is the problem particular to IPAD or does it also occur on iPhone physical devices? Can you please suggest a solution or a workaround in the code?
Thank you so much
Ad Langenkamp