Wi-Fi Calling Fails (T-Mobile)

[jazman_777]

Since the update to Oreo my Wi-Fi calling fails in various ways.

Right now it says: ER04 - DNS Error

But I've seen other errors.

Only way to fix is to restart the phone.

This is happening at home and at work networks.

For now I've simply disabled WiFi calling.

 

[Rukbat]

I'd let it fail, then bring it into TMO and ask them to fix it.

 

[jazman_777]

I rebooted into safe mode, and things worked OK. So I knew it was an app.

I unintalled all the network-related apps. It turns out it was MyDataManager, which tracks usage.

This is the first time I've had such a problem with an app, where it would break some functionality.