Use the following setup to avoid the error:
AWI uses HTTPS and ARA uses HTTP -> ok
AWI uses HTTP and ARA uses HTTP -> ok
If in the case HTTPS is already enabled, check to see if all the Release Automation sheets have fully loaded in before clicking save (Folder Authorizations, Permissions, Approval Request). If they still have the spinning load bars in the center, then wait for all of them to load before making saving.