diff --git a/githubapp/azuread.py b/githubapp/azuread.py
index a77e14e..651ac47 100644
--- a/githubapp/azuread.py
+++ b/githubapp/azuread.py
@@ -107,7 +107,11 @@ def get_group_members(self, token=None, group_name=None):
                 else:
                     username = user_info[self.USERNAME_ATTRIBUTE]
                 if self.AZURE_USER_IS_UPN:
-                    username = username.split("@")[0]
+                    if r"\\" in username:
+                        username = username.split(r"\\")[1]
+                    username = username.split("@")[0].split("#")[0].split("_")[0]
+                    username = username.translate(str.maketrans("._!#^~", "------"))
+                    username = username.lower()
                 if "EMU_SHORTCODE" in os.environ:
                     username = username + "_" + os.environ["EMU_SHORTCODE"]
                 user = {