diff --git a/programs/squads-mpl/src/lib.rs b/programs/squads-mpl/src/lib.rs
index 1ef8a31..c71a134 100644
--- a/programs/squads-mpl/src/lib.rs
+++ b/programs/squads-mpl/src/lib.rs
@@ -443,7 +443,12 @@ pub mod squads_mpl {
         let ms_key = &ctx.accounts.multisig.key();
         let ms_ix = &mut ctx.accounts.instruction;
         let tx = &mut ctx.accounts.transaction;
-        
+
+        // To prevent potential failure with the Squad account auth 0 can't be executed in a specific instruction
+        if tx.authority_index == 0 {
+            return err!(MsError::InvalidAuthorityIndex);
+        }
+
         // setup the authority seeds
         let authority_seeds = [
             b"squad",