diff --git a/app/activitypub/routes.py b/app/activitypub/routes.py
index 0b6e134a..3c95e2b5 100644
--- a/app/activitypub/routes.py
+++ b/app/activitypub/routes.py
@@ -207,18 +207,18 @@ def user_profile(actor):
     # admins can view deleted accounts
     if current_user.is_authenticated and current_user.is_admin():
         if '@' in actor:
-            user: User = User.query.filter_by(ap_id=actor).first()
+            user: User = User.query.filter_by(ap_id=actor.lower()).first()
         else:
             user: User = User.query.filter_by(user_name=actor, ap_id=None).first()
             if user is None:
                 user = User.query.filter_by(ap_profile_id=f'https://{current_app.config["SERVER_NAME"]}/u/{actor}', deleted=False, ap_id=None).first()
     else:
         if '@' in actor:
-            user: User = User.query.filter_by(ap_id=actor, deleted=False, banned=False).first()
+            user: User = User.query.filter_by(ap_id=actor.lower(), deleted=False, banned=False).first()
         else:
             user: User = User.query.filter_by(user_name=actor, deleted=False, ap_id=None).first()
             if user is None:
-                user = User.query.filter_by(ap_profile_id=f'https://{current_app.config["SERVER_NAME"]}/u/{actor}', deleted=False, ap_id=None).first()
+                user = User.query.filter_by(ap_profile_id=f'https://{current_app.config["SERVER_NAME"]}/u/{actor.lower()}', deleted=False, ap_id=None).first()
 
     if user is not None:
         if request.method == 'HEAD':
diff --git a/app/activitypub/util.py b/app/activitypub/util.py
index 1dff886d..643e9bb6 100644
--- a/app/activitypub/util.py
+++ b/app/activitypub/util.py
@@ -569,7 +569,7 @@ def actor_json_to_model(activity_json, address, server):
                         indexable=activity_json['indexable'] if 'indexable' in activity_json else False,
                         searchable=activity_json['discoverable'] if 'discoverable' in activity_json else True,
                         created=activity_json['published'] if 'published' in activity_json else utcnow(),
-                        ap_id=f"{address}@{server}",
+                        ap_id=f"{address.lower()}@{server.lower()}",
                         ap_public_url=activity_json['id'],
                         ap_profile_id=activity_json['id'].lower(),
                         ap_inbox_url=activity_json['endpoints']['sharedInbox'] if 'endpoints' in activity_json else activity_json['inbox'] if 'inbox' in activity_json else '',
@@ -628,7 +628,7 @@ def actor_json_to_model(activity_json, address, server):
                               private_mods=activity_json['privateMods'] if 'privateMods' in activity_json else False,
                               created_at=activity_json['published'] if 'published' in activity_json else utcnow(),
                               last_active=activity_json['updated'] if 'updated' in activity_json else utcnow(),
-                              ap_id=f"{address[1:]}@{server}" if address.startswith('!') else f"{address}@{server}",
+                              ap_id=f"{address[1:].lower()}@{server.lower()}" if address.startswith('!') else f"{address}@{server}",
                               ap_public_url=activity_json['id'],
                               ap_profile_id=activity_json['id'].lower(),
                               ap_followers_url=activity_json['followers'],