diff --git a/internal/autocert/manager.go b/internal/autocert/manager.go
index eca3a2f4c..4b3285542 100644
--- a/internal/autocert/manager.go
+++ b/internal/autocert/manager.go
@@ -150,7 +150,7 @@ func (mgr *Manager) getCertMagicConfig(ctx context.Context, cfg *config.Config)
 	}
 	// add existing certs to the cache, and staple OCSP
 	for _, cert := range certs {
-		if err := mgr.certmagic.CacheUnmanagedTLSCertificate(ctx, cert, nil); err != nil {
+		if _, err := mgr.certmagic.CacheUnmanagedTLSCertificate(ctx, cert, nil); err != nil {
 			return nil, fmt.Errorf("config: failed caching cert: %w", err)
 		}
 	}