diff --git a/packages/twenty-server/src/modules/contact-creation-manager/utils/filter-out-contacts-from-company-or-workspace.util.ts b/packages/twenty-server/src/modules/contact-creation-manager/utils/filter-out-contacts-from-company-or-workspace.util.ts
index f8b53017c..b06b6931a 100644
--- a/packages/twenty-server/src/modules/contact-creation-manager/utils/filter-out-contacts-from-company-or-workspace.util.ts
+++ b/packages/twenty-server/src/modules/contact-creation-manager/utils/filter-out-contacts-from-company-or-workspace.util.ts
@@ -9,16 +9,20 @@ export function filterOutSelfAndContactsFromCompanyOrWorkspace(
   connectedAccount: ConnectedAccountWorkspaceEntity,
   workspaceMembers: WorkspaceMemberWorkspaceEntity[],
 ): Contact[] {
-  const selfDomainName = getDomainNameFromHandle(connectedAccount.handle);
+  const selfDomainName = getDomainNameFromHandle(
+    connectedAccount.handle,
+  ).toLowerCase();
 
   const allHandles = [
-    connectedAccount.handle,
-    ...(connectedAccount.handleAliases?.split(',') || []),
+    connectedAccount.handle.toLowerCase(),
+    ...(connectedAccount.handleAliases?.split(',') || []).map((handle) =>
+      handle.toLowerCase(),
+    ),
   ];
 
   const workspaceMembersMap = workspaceMembers.reduce(
     (map, workspaceMember) => {
-      map[workspaceMember.userEmail] = true;
+      map[workspaceMember.userEmail.toLowerCase()] = true;
 
       return map;
     },
@@ -26,13 +30,13 @@ export function filterOutSelfAndContactsFromCompanyOrWorkspace(
   );
 
   const isDifferentDomain = (contact: Contact, selfDomainName: string) =>
-    getDomainNameFromHandle(contact.handle) !== selfDomainName;
+    getDomainNameFromHandle(contact.handle).toLowerCase() !== selfDomainName;
 
   return contacts.filter(
     (contact) =>
       (isDifferentDomain(contact, selfDomainName) ||
         !isWorkDomain(selfDomainName)) &&
-      !workspaceMembersMap[contact.handle] &&
-      !allHandles.includes(contact.handle),
+      !workspaceMembersMap[contact.handle.toLowerCase()] &&
+      !allHandles.includes(contact.handle.toLowerCase()),
   );
 }