diff --git a/internal/ctsubmit/logic.go b/internal/ctsubmit/logic.go
index 1f64a1f..c941732 100644
--- a/internal/ctsubmit/logic.go
+++ b/internal/ctsubmit/logic.go
@@ -107,7 +107,7 @@ func (d *stageZeroData) stageZero(ctx context.Context, reqBody io.ReadCloser, pr
 
 	chain, err := ctfe.ValidateChain(req.Chain, validationOpts)
 	if err != nil {
-		return nil, http.StatusBadRequest, fmt.Errorf("unable to validate chain: %w", err)
+		return nil, http.StatusBadRequest, fmt.Errorf("unable to validate chain: %w. Root issuer: %+v", err, chain[len(chain)-1].Issuer)
 	}
 
 	isPrecert, err := ctfe.IsPrecertificate(chain[0])