Activesync exchange 2016 , not work and get error 401 from server

The iAPP should be fine. The issue is likely with how to understand how this particular Exchange service is configured to work, which can be confusing. You need to work with Exchange admin to find out.

You can set up a test env on F5 with a TCP profile / passthrough only,. and find out if that works and what response you should get from the backend server for that activesync URL.