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. This license is only to allow end-user access to the platform and has no bearing on the number of emails to monitor for that SMB or MME. This will only occur if you are trying to add Organization Users. If you do not wish to add any end-users the ability to log into the platform, you can leave this as 0 and continue adding the SMB/MME.
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.