diff --git a/pkg/core/native/management.go b/pkg/core/native/management.go
index 217168afc..a216fa950 100644
--- a/pkg/core/native/management.go
+++ b/pkg/core/native/management.go
@@ -265,8 +265,9 @@ func (m *Management) Deploy(d dao.DAO, sender util.Uint160, neff *nef.File, mani
 	if err != nil {
 		return nil, err
 	}
-	if !manif.IsValid(h) {
-		return nil, errors.New("invalid manifest for this contract")
+	err = manif.IsValid(h)
+	if err != nil {
+		return nil, fmt.Errorf("invalid manifest: %w", err)
 	}
 	newcontract := &state.Contract{
 		ID:       id,
@@ -322,8 +323,9 @@ func (m *Management) Update(d dao.DAO, hash util.Uint160, neff *nef.File, manif
 		if manif.Name != contract.Manifest.Name {
 			return nil, errors.New("contract name can't be changed")
 		}
-		if !manif.IsValid(contract.Hash) {
-			return nil, errors.New("invalid manifest for this contract")
+		err = manif.IsValid(contract.Hash)
+		if err != nil {
+			return nil, fmt.Errorf("invalid manifest: %w", err)
 		}
 		m.markUpdated(hash)
 		contract.Manifest = *manif
diff --git a/pkg/smartcontract/manifest/manifest.go b/pkg/smartcontract/manifest/manifest.go
index 3a593ea21..d8afdd5a9 100644
--- a/pkg/smartcontract/manifest/manifest.go
+++ b/pkg/smartcontract/manifest/manifest.go
@@ -71,13 +71,15 @@ func (m *Manifest) CanCall(hash util.Uint160, toCall *Manifest, method string) b
 }
 
 // IsValid checks whether the hash given is correct wrt manifest's groups.
-func (m *Manifest) IsValid(hash util.Uint160) bool {
+func (m *Manifest) IsValid(hash util.Uint160) error {
+	var err error
 	for _, g := range m.Groups {
-		if !g.IsValid(hash) {
-			return false
+		err = g.IsValid(hash)
+		if err != nil {
+			break
 		}
 	}
-	return true
+	return err
 }
 
 // ToStackItem converts Manifest to stackitem.Item.
diff --git a/pkg/smartcontract/manifest/manifest_test.go b/pkg/smartcontract/manifest/manifest_test.go
index 629bea1d9..c92dcd289 100644
--- a/pkg/smartcontract/manifest/manifest_test.go
+++ b/pkg/smartcontract/manifest/manifest_test.go
@@ -112,7 +112,7 @@ func TestIsValid(t *testing.T) {
 	m := NewManifest("Test")
 
 	t.Run("valid, no groups", func(t *testing.T) {
-		require.True(t, m.IsValid(contractHash))
+		require.NoError(t, m.IsValid(contractHash))
 	})
 
 	t.Run("with groups", func(t *testing.T) {
@@ -129,11 +129,11 @@ func TestIsValid(t *testing.T) {
 		}
 
 		t.Run("valid", func(t *testing.T) {
-			require.True(t, m.IsValid(contractHash))
+			require.NoError(t, m.IsValid(contractHash))
 		})
 
 		t.Run("invalid, wrong contract hash", func(t *testing.T) {
-			require.False(t, m.IsValid(util.Uint160{4, 5, 6}))
+			require.Error(t, m.IsValid(util.Uint160{4, 5, 6}))
 		})
 
 		t.Run("invalid, wrong group signature", func(t *testing.T) {
@@ -145,7 +145,7 @@ func TestIsValid(t *testing.T) {
 				// of the contract hash.
 				Signature: pk.Sign([]byte{1, 2, 3}),
 			})
-			require.False(t, m.IsValid(contractHash))
+			require.Error(t, m.IsValid(contractHash))
 		})
 	})
 }
diff --git a/pkg/smartcontract/manifest/method.go b/pkg/smartcontract/manifest/method.go
index b3ef30ab9..e56a89165 100644
--- a/pkg/smartcontract/manifest/method.go
+++ b/pkg/smartcontract/manifest/method.go
@@ -56,8 +56,11 @@ func NewParameter(name string, typ smartcontract.ParamType) Parameter {
 }
 
 // IsValid checks whether group's signature corresponds to the given hash.
-func (g *Group) IsValid(h util.Uint160) bool {
-	return g.PublicKey.Verify(g.Signature, hash.Sha256(h.BytesBE()).BytesBE())
+func (g *Group) IsValid(h util.Uint160) error {
+	if !g.PublicKey.Verify(g.Signature, hash.Sha256(h.BytesBE()).BytesBE()) {
+		return errors.New("incorrect group signature")
+	}
+	return nil
 }
 
 // MarshalJSON implements json.Marshaler interface.