When trying to add an SMB or MME user, I get the following error message:
Unable to create user: Unprocessable Entity: User seat limit reached.
As of April 18th, 2020 we added the ability to place a limit on the number of users allocated to your SMB or MME. You will have a pool of user licenses, that can be allocated as you wish.
Under the main page for DWID, look for the SMB or MME and select EDIT.
This will open the settings for this particular SMB, and just navigate towards the middle and allocate the user seats available.