Here is a info for everyone still wondering about that:
I just was able to buy a print-at-home ticket from Austria also by entering 999-999-9999 as my phone number.
Today, Greyhound support finally replied to my inquiry. I’ll add a part of the reply here, as it also answers this question and is directly from Greyhound:
In reference to your question, International Customers may attempt
your purchase by selecting a random State/Providence, if there is an
error with reading the billing address. Also, you may type in as many
characters as possible in the phone number field or you may type in
999-999-9999. This may be able to assist in regards to purchasing
online. If you are to continue to run into an error while attempting
your purchase, please Contact our Greyhound International line at,
800-246-8572/212-971-0492 to assist with booking your ticket. Our IT
team is aware of the situation is currently working on fixating the
issue.
Credit:stackoverflow.com‘
4 Mar, 2024
5 Mar, 2024
4 Mar, 2024