diff --git a/kallithea/controllers/login.py b/kallithea/controllers/login.py
--- a/kallithea/controllers/login.py
+++ b/kallithea/controllers/login.py
@@ -82,7 +82,7 @@ class LoginController(BaseController):
                 c.form_result = login_form.to_python(dict(request.POST))
                 # form checks for username/password, now we're authenticated
                 username = c.form_result['username']
-                user = User.get_by_username_or_email(username, case_insensitive=True)
+                user = User.get_by_username_or_email(username)
                 assert user is not None  # the same user get just passed in the form validation
             except formencode.Invalid as errors:
                 defaults = errors.value
diff --git a/kallithea/lib/auth_modules/__init__.py b/kallithea/lib/auth_modules/__init__.py
--- a/kallithea/lib/auth_modules/__init__.py
+++ b/kallithea/lib/auth_modules/__init__.py
@@ -136,9 +136,6 @@ class KallitheaAuthPluginBase(object):
                   username)
         if username:
             user = User.get_by_username_or_email(username)
-            if user is None:
-                log.debug('Fallback to fetch user in case insensitive mode')
-                user = User.get_by_username(username, case_insensitive=True)
         else:
             log.debug('provided username:`%s` is empty skipping...', username)
         return user
diff --git a/kallithea/model/db.py b/kallithea/model/db.py
--- a/kallithea/model/db.py
+++ b/kallithea/model/db.py
@@ -549,7 +549,7 @@ class User(Base, BaseDbModel):
         return user
 
     @classmethod
-    def get_by_username_or_email(cls, username_or_email, case_insensitive=False, cache=False):
+    def get_by_username_or_email(cls, username_or_email, case_insensitive=True, cache=False):
         """
         For anything that looks like an email address, look up by the email address (matching
         case insensitively).