Errors "Setting site role for user to '<siterole>' failed" or "Insufficient licenses. Setting user roles to '<siterole>' failed."

Issue

When attempting to add a new user or assign a site role to a user on Tableau Server, one of the following error messages might occur:

Setting site role for user <username> to '<siterole>' failed

Insufficient licenses. Setting user roles to '<siterole>' failed.

Environment

Tableau Server

Resolution

Verify that all interactor keys are activated within Manage Product Keys. For more information, see Add Capacity to Tableau Server.
Ensure that all interactor keys are refreshed with an active maintenance date. For more information, see Refresh Maintenance Date for the Product Key.
Restart Tableau Server using the following commands to synchronize Tableau Server with the Trusted Storage.

tabadmin stop
lmreread
tabadmin start

In a multi Site Tableau Server Environment:

If Tableau Server is reflecting the correct number of licenses available on an individual site, but still unable to add a new user:

Select Manage All Sites and review the full list of users.
Confirm that the number of users on All Sites does not exceed the number of license seats.

Cause

When attempting to add a new user or assign a site role to a user on Tableau Server, the Tableau Server environment has reached or exceeded the total number of available Interactor seats.