Some things to look out for:
1. Is ENVI closed on other clients accessing the license or is it still in use?
This error is thrown when there are an inadequate number of seats - do you have enough seats?
NOTE: you can check this by opening the Harris License Administrator tool from a client pointing to the server, selecting "View Licenses" and checking the 2 boxes to the right, involving showing in-use counts. Refresh this using the refresh icon to check if seats are in use and make sure you have adequate seats.

2. Is there a firewall blocking connectivity for the troublesome clients? Is the default port 7070 for client-server communication enabled?

3. Read/Write/Execute permissions are needed on the /harris/license/flexera and /harris/license/flexera-sv folders for each user of the ENVI 5.4.1 software. This is the requirement for all licensing mode (node locked and floating), and even for client machines of a license server. I would check the permissions on these folders. Being unable to write to these folders for some clients may also be holding up access to the license seats.

Hi

I've got the same error on ubuntu 18.04. After successful activation still getting error:

IDL 8.7.3 (linux x86_64 m64).
(c) 2020, Harris Geospatial Solutions, Inc.

% Failed to acquire license.
% A license is not available to run this product. Use the license administration utility to determine
which licenses are available or activate an entitlement.


Maybe I need to run envi in some other way than .../harris/envi55/bin/envi ?
Suggestions described above didn't help.

Please for help