diff --git a/validator/keymanager/remote-web3signer/internal/client.go b/validator/keymanager/remote-web3signer/internal/client.go
index 26ef849dd..e76d9922e 100644
--- a/validator/keymanager/remote-web3signer/internal/client.go
+++ b/validator/keymanager/remote-web3signer/internal/client.go
@@ -10,6 +10,7 @@ import (
 	"net/http/httputil"
 	"net/url"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/ethereum/go-ethereum/common/hexutil"
@@ -74,14 +75,13 @@ func (client *ApiClient) Sign(ctx context.Context, pubKey string, request SignRe
 		return nil, fmt.Errorf("signing operation failed due to slashing protection rules,  Signing Request URL: %v, Status: %v", client.BaseURL.String()+requestPath, resp.StatusCode)
 	}
 	contentType := resp.Header.Get("Content-Type")
-	switch contentType {
-	case "application/json":
+	if strings.HasPrefix(contentType, "application/json") {
 		var sigResp SignatureResponse
 		if err := unmarshalResponse(resp.Body, &sigResp); err != nil {
 			return nil, err
 		}
 		return bls.SignatureFromBytes(sigResp.Signature)
-	default:
+	} else {
 		return unmarshalSignatureResponse(resp.Body)
 	}
 }
diff --git a/validator/keymanager/remote-web3signer/internal/client_test.go b/validator/keymanager/remote-web3signer/internal/client_test.go
index 7796090f3..793e5d27a 100644
--- a/validator/keymanager/remote-web3signer/internal/client_test.go
+++ b/validator/keymanager/remote-web3signer/internal/client_test.go
@@ -59,10 +59,10 @@ func TestClient_Sign_HappyPath_Jsontype(t *testing.T) {
 	}
 	jsonBytes, err := json.Marshal(sigResp)
 	require.NoError(t, err)
+	require.NoError(t, err)
 	// create a new reader with that JSON
-	header := http.Header{
-		"Content-Type": []string{"application/json"},
-	}
+	header := http.Header{}
+	header.Set("Content-Type", "application/json;  charset=UTF-8")
 	r := io.NopCloser(bytes.NewReader(jsonBytes))
 	mock := &mockTransport{mockResponse: &http.Response{
 		StatusCode: 200,