The Geocortex security users of 3.15 are not transferred to the 4.0,

The Geocortex security users of 3.15 are not transferred to the 4.0,

I wanted to upgrade to 4.0 (form 3.15.) In one of the test machines, the Geocortex security users that are built in 3.15 are not transferred to the 4.0.

How to ensure transfering the Geocortex users when upgrading to 4.0?

What might be the issue here?

Thank you

Best

Jamal