Blocking dates in my calendar

[Thom19]

Hi as I can't sync the air b and b calendar with the booking.com calendar but am listed on both sites - I f I get a booking with Booking.com I have to manualy block those dates on my air b and b calendar. When I atempt to do this I get this message quite a lot of the time:

We’re sorry, something went wrong. Please try again later.

This got me into a bit of trouble the other day as a guest did a confirmed last minute booking via air b and b because the air b and b system had failed to let me block the dates there was a clash with a pre-ceeding booking via booking.com

Help!!

Thom