diff --git a/src/constants/messages.ts b/src/constants/messages.ts
index 6a552940..1910837a 100644
--- a/src/constants/messages.ts
+++ b/src/constants/messages.ts
@@ -123,6 +123,7 @@ export const FAILURE_MESSAGES = {
   ACCOUNT_NOT_FOUND: 'ACCOUNT_NOT_FOUND',
   CANNOT_CREATE_MEMBERSHIP_CAUSE_ITEM_LOGIN_SCHEMA_EXISTS:
     'CANNOT_CREATE_MEMBERSHIP_CAUSE_ITEM_LOGIN_SCHEMA_EXISTS',
+  CANNOT_MODIFY_GUEST_ITEM_MEMBERSHIP: 'CANNOT_MODIFY_GUEST_ITEM_MEMBERSHIP',
 };
 
 export const DEFAULT_FAILURE_MESSAGE = FAILURE_MESSAGES.UNEXPECTED_ERROR;
diff --git a/src/langs/en/messages.json b/src/langs/en/messages.json
index 4a6952fd..3427c3b9 100644
--- a/src/langs/en/messages.json
+++ b/src/langs/en/messages.json
@@ -144,5 +144,6 @@
   "NOT_A_MEMBER": "Your account is not registered as a valid member",
   "NOT_A_GUEST": "Your account is not registered as a valid pseudonimized user",
   "ACCOUNT_NOT_FOUND": "An account was not found",
-  "CANNOT_CREATE_MEMBERSHIP_CAUSE_ITEM_LOGIN_SCHEMA_EXISTS": "You cannot request a membership because the targeted ressource allows pseudonimized users"
+  "CANNOT_CREATE_MEMBERSHIP_CAUSE_ITEM_LOGIN_SCHEMA_EXISTS": "You cannot request a membership because the targeted ressource allows pseudonimized users",
+  "CANNOT_MODIFY_GUEST_ITEM_MEMBERSHIP": "Cannot modify the permission of targeted account because it is a pseudonimized user"
 }