diff --git a/server/mergin/sync/public_api.yaml b/server/mergin/sync/public_api.yaml
index 48d39c13..c8072ad6 100644
--- a/server/mergin/sync/public_api.yaml
+++ b/server/mergin/sync/public_api.yaml
@@ -1044,6 +1044,23 @@ components:
         detail: Maximum number of people in this workspace is reached. Please upgrade your subscription to add more people (UsersLimitHit)
         rejected_emails: [ rejected@example.com ]
         users_quota: 6
+    EditorsLimitHit:
+      allOf:
+        - $ref: '#/components/schemas/CustomError'
+      type: object
+      properties:
+        rejected_emails:
+          nullable: true
+          type: array
+          items:
+            type: string
+        editors_quota:
+          type: integer
+      example:
+        code: EditorsLimitHit
+        detail: Maximum number of editors in this workspace is reached. Please upgrade your subscription to add more (EditorsLimitHit)
+        rejected_emails: [ rejected@example.com ]
+        editors_quota: 6
     UpdateProjectAccessError:
       allOf:
         - $ref: '#/components/schemas/CustomError'
diff --git a/server/mergin/sync/public_api_controller.py b/server/mergin/sync/public_api_controller.py
index 77faeec2..6a39e441 100644
--- a/server/mergin/sync/public_api_controller.py
+++ b/server/mergin/sync/public_api_controller.py
@@ -680,11 +680,34 @@ def update_project(namespace, project_name):  # noqa: E501  # pylint: disable=W0
     """
     project = require_project(namespace, project_name, ProjectPermissions.Update)
     parsed_access = parse_project_access_update_request(request.json.get("access", {}))
+
+    # get current status for easier rollback
+    modified_user_ids = []
+    for role in list(ProjectRole.__reversed__()):
+        modified_user_ids.extend(parsed_access.get(role, []))
+    current_permissions_map = {
+        user_id: project.get_role(user_id) for user_id in modified_user_ids
+    }
+
     # get set of modified user_ids and possible (custom) errors
     id_diffs, error = current_app.ws_handler.update_project_members(
         project, parsed_access
     )
 
+    # revert back rejected changes
+    if error and hasattr(error, "rejected_emails"):
+        rejected_users = (
+            db.session.query(User.id)
+            .filter(User.email.in_(error.rejected_emails))
+            .all()
+        )
+        for user in rejected_users:
+            if current_permissions_map[user.id] is None:
+                project.unset_role(user.id)
+            else:
+                project.set_role(user.id, current_permissions_map[user.id])
+        db.session.commit()
+
     if not id_diffs and error:
         # nothing was done but there are errors
         return jsonify(error.to_dict()), 422