This error can often be resolved by either editing the hosting username or by deleting and re-adding the hosting user: https://kb.blackbaud.com/articles/Article/40016

The existing hosting username can be edited to make it unique and resolve the error by following these steps.

If recreating the user does not resolve the issue, click Chat with Support and reference this article. Please provide the analyst with the following information:

  1. Document the exact wording of the error message.
  2. The Hosting username of the affected user.
  3. List the exact steps to duplicate the issue.