I deployed the Communications Utility Network Foundation v1.6 and reviewed the documentation. I downloaded the zipped project and opened it in ArcGIS Pro 3.5.
I started following the tasks that were set up in the project. One task asks me to expand the Communications_UtilityNetwork database and review a feature class.
When trying to expand the database I get this error.

The same thing happens when try to expand the Configurations database. These two databases are mobile geodabases with a .geodatabase extension. I haven't worked with these before. There are two other databases that are file geodatabases with the .gdb folder. They work fine.

I've tried to reconnect them and remove and re-add them, but they are unreadable. What can I do to continue to use the foundation?