Anyone having these error messages at final step in the booking process.
This occurred attempting a Mr & Mrs Smith property booking
10-14 days ago: APP worked, .COM didn't
Today: both .COM and .APP do not work, giving the error messages below.

1. Hyatt.COM "Unknown Error" (no other details provided, so how to diagnose how/why occurring? )
2. Hyatt.APP "We're sorry, we could not complete the booking for you. Please call customer service."

With the APP, can clear cache, clear data, reinstall.
With .COM, cannot reinstall.

So, is the loyalty member supposed to :
i. make all future reservations by telephone ?
ii. try to diagnose & solve the problem, since Hyatt doesn't know why eg. make some "test" bookings (fully refundable, some dates into future, try pure Hyatt and Hyatt "partners" (eg. Mr Smith , Alua, etc)

More time wasted