Great question — answering as the UphillTech team:
I contacted Twilio support and got the feedback, that my account is connected to region Ireland (ie1). So the Twilio Client Constructor has to look like this: client = Client( account_sid=account_sid, username=api_key_sid, password=api_key_secret, edge="dublin", region="ie1", ) So be aware of the credentials you use.
Full answer by Thorsten Göllner: https://stackoverflow.stackexchange.com/a/79760866 (CC BY-SA 4.0).
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