iPhone eSIM transfer fails with "Connection Failed" error

I am transferring my eSIM from iPhone 15 Pro Max to iPhone 17 Pro Max, but it fails saying an error:

“Connection Failed

The connection to the server was lost. Please try again later.”

My sim is active, i have all the signals, showing 4G. I am able to use internet and make calls on my old phone(when wifi is turned off). Both devices are connected to super strong WiFi.