Hello,
I have troubles accessing my Developer Dashboard.
I am in Ukraine, and I am starting development for a client in the USA. The client created an account and assigned full access for my account. At first I was able to login and verify my ukrainian phone number. Even though I had to use VPN to access the web site, not a big problem.
But now I can’t pass 2FA because the SMS codes not arriving.
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This is expected since Square has made a business decision to block traffic in Ukraine. 
Yeah, this is so dumb. Why then I was able to register and confirm my phone number in the first place? I am just a software developer, I am not a client to Square and I don’t conduct any business activity with Square. I just need to test my code, which will run on servers where ever Square wants.
It is so funny. I tried one more time to receive an SMS, and it worked. At least for now I logged in to my dev dashboard.
Hello,
I am facing the same issue again. No SMS codes are reaching me. 
@Bryan-Square what countries did you block? I am unable to login from Poland. I was asked to Opt-In which I did, neither SMS text messages nor the Voice verification worked.
Now my account show: Your account has been locked temporarily. Please try again later.
UPDATE
I managed to login using Passkey I forgot I have set up. But when I got into security settings to add additional MFA options I was asked to verify with different prompt. I send START and them HELP messages to number specified but I did not receive any messages in response 
I can’t update any setting related to authentication, it looks like catch 22 situation.
Glad to hear that you got in again.