The License Manager that ships with FaceFX Professional 2017.1 requires .NET 4.7.1 to connect to the license server, but does not install this requirement automatically.
An updated installer can be downloaded here. This version also fixes a crash in the license manager if the Windows setting "System cryptography: use FIPS compliant algorithms for encryption, hashing, and signing" is enabled.
If you prefer, you can install .NET manually and make sure that the FIPS setting is disabled (the default value) while using the standard License Manager that ships with FaceFX Studio 2017.1.
Updating to the latest License Manager is encouraged, even if you are using an older version of FaceFX Studio Professional.