Unable to use the 'Add to groups' option in ArcGIS Enterprise 11.3.

Additional Information

Workaround

The workflow can be accomplished by navigating through the following steps:

1. At the top of the site, click Organization, and then click the Members tab.
2. Select the member or members for the assignment to a group or groups, click More, then click Manage Group Membership.
3. In the next window, select a member or members for assignment to a selected group or groups.
4. Click Save.

Steps to Reproduce