There's a lot of unknown to determine what the issue is. Maybe the following help get you started:
1. Verify you have indeed upgraded to Portal 10.8 or 10.8.1. An easy option is to check in Programs and Features in the Control Panel.
2. Verify you have the correct version of the license file (.json file).
3. Verify you have the user types mentioned in your description. You can view the details in MyEsri. In doing so, make sure you downloaded and copy the correct json file.
If you've verified all the above, the next thing is to verify the content of the json file. For this, I recommend you contact the distributor or Esri Technical Support. An analyst can help review the content of the json file.