iphone 13 pro max Wifi calling enable error

Hello silambu83!

Since Wi-Fi Calling is a Carrier Feature, you may want to contact your Carrier for further assistance.

If your Carrier confirms there is no issue with your account, please reach out to Apple Support:

• Telephone: Contact Apple for support and service - Apple Support. 
• Online: Start your request online. 
• Chat: Live Chat with an Apple Advisor in Messges. 
• More Contacting Info: Contact - How to Contact Us - Apple. 

I hope this is helpful. Good Luck!

See where it says “Terms and Conditions?” Tap on the circle below that, and then “Continue,” and see if it’ll go away.