diff --git a/website_membership_registration/models/res_partner.py b/website_membership_registration/models/res_partner.py
index 9e74c8e..68a9c7a 100644
--- a/website_membership_registration/models/res_partner.py
+++ b/website_membership_registration/models/res_partner.py
@@ -68,7 +68,7 @@ def _compute_membership_group_ids(self):
             )
         return res
 
-    @api.constrains("email", "membership_state")
+    @api.constrains("email", "membership_state", "active")
     def _check_mail_unique(self):
         for partner in self:
             if not partner.email or partner.membership_state == "none":
@@ -78,9 +78,10 @@ def _check_mail_unique(self):
             self.env.cr.execute(
                 """
                     SELECT id FROM res_partner
-                    WHERE email ILIKE %s
+                    WHERE LOWER(email) = LOWER(%s)
                     AND id != %s
                     AND membership_state != 'none'
+                    AND active = TRUE
                     LIMIT 1
                 """,
                 (partner.email, partner.id),