Issues with Threema and WIFI connection

REPRODUCIBILITY (% or how often): 100%
HARDWARE: Sony Xperia 10 (DUAL SIM)

I have a running Threema application (messaging app) in the android layer.
Calls (audio/video) are working when using the mobile internet connection (4G.
When switch to WIFI calls does not get established. The call arrives at the recipient
but accepting/establishing does not work. This happens only when on WIFI connections.

This is in particular strange because using a different app like Wire (messaging app).
Calls are working over mobile and Wifi connections.

Does the namespace/sandbox of the android layer especially in the case of
the Threema app has networking/routing problems when switching to Wifi?

I appreciate any hints.

A solution in the next release would be great!


That’s a long standing bug, see here. Would be really nice if finally addressed though.

Thanks for the feedback.

I am currently living with the following compromise solution.

  1. check at the connection status if “Mobile data” is displayed.
  2. if so, deactivate the Wi-Fi connection for a short time until the name of the telephony provider is displayed instead of “Mobile data”.
  3. then turn on the Wi-Fi connection again and make sure that the name of the telephony provider is still there.

According to WebRTC diagnostics, the routing in Threema will then run via Wi-Fi. In most cases, this diagnosis ends in a time-out. Nevertheless, audio and video telephony seem to work.

Thanks, normally I think that I am skilled enough but for this workflow not yet :slight_smile: .
Could you explain the steps in more detail? I would like to test this workaround. This would be great!

Maybe you are not skilled enough for my bad English. :smiley:
Hopefully pictures speak more than words.
The goal is to get rid of this “mobile data” and still have Wi-Fi active.

Step 1

Step 2

Step 3

Unbelievable, it worked yesterday. Today I had problems to find the exact timing in switching WIFI on/off but it worked. This race-condition is definitely a bug. They must be more easter eggs like this :-). Thanks.

This may lead to kind of a hybrid phone behaviour between wifi and mobile connection. In this case the wifi symbol in the top right corner regularly alternates with the mobile connection symbol during data usage. Actually I am not sure which connection is effectively used.

I see in at least two different apps that Wi-Fi is always given priority. Also, I’ve been using it this way for quite some time now and I don’t see any increased usage of mobile data connections.