How to fix SmsChallengeRiskRejection_flightOn "We’re unable to validate your phone number"

Question

Hello,
I am unable to sign up to Azure cloud services because phone verification does not work.
I am located in France with a french phone number.
I tried :

• Different phone number
• Different browser
• Different network
• Different device

I tried the sms and the call me option.

Nothing works, i always get the error "We’re unable to validate your phone number" when clicking either sms or call me button.
The request in the network tabs returns : "SmsChallengeRiskRejection_flightOn"