Error when logging in to SDL MultiTerm 2017 Administrator Plugin: Value cannot be null Parameter name: usrCredentials

You attempt to log into MultiTerm Server via SDL MultiTerm Desktop 2017's MultiTerm Administrator plugin.
You receive following error:

Value cannot be null
Parameter name: usrCredentials

Workaround: Use 'Do not prompt me again' feature

In the Log in to SDL Server dialog:

1. Enter your credentials
2. Enable the option Do not prompt me again

Note: Unlike for MultiTerm 2015 Desktop/Administrator, it is not longer necessary to manually delete credential files.

This behavior can be seen when connecting to MultiTerm Server via https. The SDL Development team is aware of this problem and is working on a solution. Until a permanent solution is in place, apply the workaround described below.