Microsoft default installation of Exchange Server 2019 does not  support TLS 1.0 and 1.1   TLS 1.2 and above is supported.

https://docs.microsoft.com/en-us/exchange/architecture/client-access/certificates?view=exchserver-2019

Customers who plan to install \ upgrade to Exchange 2019 and who have an existing fax server running on Windows 2012 R2 will need a patch from BNS to support Exchange 2019.

Customers who plan to install a new fax server will be required to install on Windows Server 2016 or better using the latest software release of msXfax.