diff --git a/consensus/bor/bor.go b/consensus/bor/bor.go
index a8f90dfe66..fac5500b76 100644
--- a/consensus/bor/bor.go
+++ b/consensus/bor/bor.go
@@ -555,7 +555,8 @@ func (c *Bor) verifySeal(chain consensus.ChainReader, header *types.Header, pare
 		return err
 	}
 	if !snap.ValidatorSet.HasAddress(signer.Bytes()) {
-		return &UnauthorizedSignerError{number, signer.Bytes()}
+		// Check the UnauthorizedSignerError.Error() msg to see why we pass number-1
+		return &UnauthorizedSignerError{number - 1, signer.Bytes()}
 	}
 
 	succession, err := snap.GetSignerSuccessionNumber(signer)
@@ -741,7 +742,8 @@ func (c *Bor) Seal(chain consensus.ChainReader, block *types.Block, results chan
 
 	// Bail out if we're unauthorized to sign a block
 	if !snap.ValidatorSet.HasAddress(signer.Bytes()) {
-		return &UnauthorizedSignerError{number, signer.Bytes()}
+		// Check the UnauthorizedSignerError.Error() msg to see why we pass number-1
+		return &UnauthorizedSignerError{number - 1, signer.Bytes()}
 	}
 
 	successionNumber, err := snap.GetSignerSuccessionNumber(signer)
diff --git a/consensus/bor/bor_test/bor_test.go b/consensus/bor/bor_test/bor_test.go
index 1c6c530e82..98331996f9 100644
--- a/consensus/bor/bor_test/bor_test.go
+++ b/consensus/bor/bor_test/bor_test.go
@@ -185,5 +185,5 @@ func TestSignerNotFound(t *testing.T) {
 	_, err := chain.InsertChain([]*types.Block{block})
 	assert.Equal(t,
 		*err.(*bor.UnauthorizedSignerError),
-		bor.UnauthorizedSignerError{Number: 1, Signer: addr.Bytes()})
+		bor.UnauthorizedSignerError{Number: 0, Signer: addr.Bytes()})
 }