Ответили:
Sorry to hear you are having trouble.
After a major release over the weekend, we have identified a bug with our tax submission form that our development team is currently working to fix. This bug is currently preventing users from submitting their completed tax form into our system for record-keeping and processing.
As we do prefer that your W8BEN be submitted electronically, we kindly ask for your patience while we correct this issue. We are estimating this issue will be fixed before the end of the week. We understand the inconvenience this may cause, and thank you in advance for your patience.
In the meantime, do let me know if you have any further questions.
В общем какие-то проблемы у них, до конца недели обещали исправить.