WiFi Calling - Cannot connect to network

[Android Central Question]

My Galaxy S6 used to do WiFi Calling, and it was great - especially since signal strength in my home is low. About a month or so ago, WiFi Calling stopped, giving only the error message "Network connection error. Please try again."

I have tried:
- Sprint Customer Support troubleshooting
- System Update
- Software Update
- PRL & Profile Update
- Clear System Cache
- Factory Reset

I am connected to WiFi, with a strong signal.
Other Galaxy S6s on my plan and in my home continue to do WiFi Calling fine, so it's not the network or my plan.
My S6 seems to be working fine otherwise.

Provider: Sprint
Android Version: 7.0
Model Number: SM-G920P
Hardware Version: G920P.02
Software Version: G920PVPS4DRC2
Android security patch level: March 1, 2018
Kernel version: 3.10.61-11881452

I'm looking for help restoring WiFi Calling.

 

[Rukbat]

Try Sprint CS again and, when they can't help you, ask them to elevate the trouble to level 2. Then, whatever level you're at, if they can't help you, ask if they could lease elevate it further. Someone there will know what the problem is.

 

[belodion]

Moved to S6 for comments from users.