Solution
This message is a bug of NI License Manager, but it is not harmful. You should be able to use your software after dismissing the message.
To avoid this message permanently you have to select
"Remind me when they expire" twice or
"Do not remind me". This works for a single software if you have multiple software licensed through the disconnected license you will have to repeat this process which each version and software.
For NILM 4.7:

For NILM 4.6:

Note: the "Remind me next time" option is only available on newer versions of NILM, from 4.6 or higher.