diff --git a/.github/workflows/oidc-conformity.yml b/.github/workflows/oidc-conformity.yml
index 6994fb5e..79e5d11e 100644
--- a/.github/workflows/oidc-conformity.yml
+++ b/.github/workflows/oidc-conformity.yml
@@ -14,7 +14,7 @@ jobs:
         with:
           fetch-depth: 2
           repository: ory/hydra
-          ref: 2866a0499d02341ed0603601cfe4e63b24506fcb
+          ref: a35e78e364a26c4f87f37d9f545ef10b3ffa468a
       - uses: actions/setup-go@v2
         with:
           go-version: "1.21"
diff --git a/handler/oauth2/flow_refresh.go b/handler/oauth2/flow_refresh.go
index 987a403b..bffddad6 100644
--- a/handler/oauth2/flow_refresh.go
+++ b/handler/oauth2/flow_refresh.go
@@ -59,7 +59,7 @@ func (c *RefreshTokenGrantHandler) HandleTokenEndpointRequest(ctx context.Contex
 			WithHint("The refresh token is malformed or not valid.").
 			WithDebug("The refresh token can not be found.")
 	} else if err != nil {
-		return fosite.ErrInvalidGrant.WithWrap(err).WithDebug(err.Error())
+		return fosite.ErrServerError.WithWrap(err).WithDebug(err.Error())
 	}
 
 	if err := c.RefreshTokenStrategy.ValidateRefreshToken(ctx, originalRequest, refresh); err != nil {