Every time you log in after logging out, we perform a SMS roundtrip. By typing your phone number, you should receive a new authentication code, i.e. previous authentication code cannot be reused.
We looked into the our server log and it looks like your login requests were handled and requests to send SMSs were successful. However, on Twilio (our SMS provider), there seem to have issues. It showed that Twilio sent messages to upstream (i.e. your phone carrier), these messages were accepted, but didn't receive confirmation messages back. There was an older message that went to the same number and successfully delivered. It matches your description.
There might be a possibility that your phone blocks receiving text messages. Some mobile carriers has customer setting of that. Another possibility is that the carrier may have issues and these messages are queued or dropped.
The expected behavior is that you are receiving a new authentication code and that lets you login. It would be great if you can try one more time after some period of time.
We support phone number-based login as it has many benefits over email-based login. One of the benefit is that it is hard to create bogus accounts. That being said, we are working on adding email-based login system for projects and it will be available near future.