Error in market data subscription form "invalid phone_number"

I want to subscripe for the unlimited market data plan. The first time in filled in the form and everything went fine, except i broke it off at the payment.

When i try to subscribe now i get an "
invalid phone_number" error. In my account settings i can see my correct phone number.

The error accurs on this page: https://app.alpaca.markets/brokerage/new-account/info-update?&upd=1&cycle=monthly

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