HTTP/2 protocol is enabled by default in Server 2016+ and Windows 10+ OS. In some older browsers or HTTP clients, you might encounter an error because the protocol is not fully supported. You can prevent these errors by disabling HTTP/2 protocol.
How to Disable HTTP/2
Open the Windows Registry Editor
Go to the following registry key:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters
Add the following DWORD values and set both values to zero.
EnableHttp2Tls
EnableHttp2Cleartext
Reboot the computer.