ArcGIS Online: Inviting members ends up with “insufficient user types” error,

[JamalNUMAN]

ArcGIS Online: Inviting members ends up with “insufficient user types” error,

Despite the fact that only one user is created (as shown in the screenshot below), inviting members ends up with “insufficient user types” error.

What could be the issue here?

[Katie_Clark]

It seems to me like it's just an issue of how many licenses you've purchased for your organization...does it say that you have any remaining? 

You can check this under the Licenses > User Types tab of the "Organization" section in ArcGIS Online (assuming you're an administrator) 

[JamalNUMAN]

It says that there are 3 users available as “viewer”, nevertheless, the error message appears.

What could be the issue here?

[Katie_Clark · Accepted solution]

It seems like you're confusing "User Type" vs. "Role". In the screenshot you posted, you're still trying to assign the user a User Type of "GIS Professional Advanced" with a Role of Viewer. This won't work because you only have one available. Changing the User Type to viewer should fix your issue. 

For reference, here is a link to Esri's page on User Types, Roles, and Privileges:

User types, roles, and privileges—ArcGIS Online Help | Documentation 

[JamalNUMAN]

Many thanks Katherine for the help. It works with me