I have sent them the following explanations, but they have not replied in six days.
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I’ve had two different errors:
1. It asks for my phone number, I enter it, and get: “You have reached the maximum number of attempts. Please try again at a later date.” but I never received any verification code.
2. Or I get a verification link, open it on my phone, and before I can fill anything in, I get: “Try later.”
That depends entirely on what you will be doing when in the U.S. While you can't work in the U.S. as a visitor, there are lots of activities that you can engage in as a founder while in the U.S. as a visitor. See one of my responses above regarding permissible activities as a visitor.
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I’ve had two different errors:
1. It asks for my phone number, I enter it, and get: “You have reached the maximum number of attempts. Please try again at a later date.” but I never received any verification code.
2. Or I get a verification link, open it on my phone, and before I can fill anything in, I get: “Try later.”