diff --git a/server/prometheus.js b/server/prometheus.js
index 870581d2..f91b0a13 100644
--- a/server/prometheus.js
+++ b/server/prometheus.js
@@ -60,7 +60,9 @@ class Prometheus {
             }
 
             try {
-                monitor_cert_days_remaining.set(this.monitorLabelValues, tlsInfo.certInfo.daysRemaining);
+                if (tlsInfo.certInfo != null) {
+                    monitor_cert_days_remaining.set(this.monitorLabelValues, tlsInfo.certInfo.daysRemaining);
+                }
             } catch (e) {
                 console.error(e);
             }