an unknown red symbol apear above the screen of my htc m8 phone. whats this?

[aam73]

i unlocked my phone, after that an unknown red symbol apear on screen, it is like a red phone. how can i fix it?

 

[lucianus_luciferus]

that shows wifi calling enabled

 

[aam73]

how can i disable this?

 

[aam73]

that shows wifi calling enabled

tanx very much, i fixed it :*