To use ArcGIS you normally have to be logged in to Arcgis.com. If you are working for a time without network connection, you may "borrow" a license.
Borrow/check out a license before working off-line
Start ArcGIS Pro in the usual way (see KI 1002How to download and install ArcGIS Pro).
Select Settings>Licensing.
Check Authorize ArcGIS Pro to work offline:
Since you will be logged out of Arcgis.com when you borrow the license, you will be asked if you want to log in first to retrieve content that you may have stored in the Arcgis.com portal. Click Yes here, and log in in the same way as when you started the program for the first time, with your UiB work/school license (Microsoft 365).
You can now work without an internet connection.
Return / check in the license when you are back online
Start ArcGIS Pro as usual.
Select Settings > Portals.
Right-click on the entry https;//www.arcgis.com and select Sign in:
Log in in the same way as when you started the program for the first time, with your UiB work/school license (Microsoft 365).
Go to Licenses again and uncheck Authorize ArcGIS Pro to work offline. You may need to log in again. Eventually the message Returning borrowed licenses will appear: