Facility to test:
Operating systeem CentOS version 7.4 supports HTTP/2.
For HTTP, suppliers of webbrowsers agreed not to support HTTP/2.
Protocols h2 h2c http/1.1
# plesk bin http2_pref disable
# plesk bin http2_pref enable
(also rewriting cipher setup)
I faced a connection error during payment where the user process did not continue after a minor internet failure. Fix: Payment Service Provider (PSP) Mollie stabilized error handling for their library.