diff --git a/client/src/Components/common/charts/HeatmapResponseTimeTooltip.tsx b/client/src/Components/common/charts/HeatmapResponseTimeTooltip.tsx
index c046e05b5..dc36ee5d9 100644
--- a/client/src/Components/common/charts/HeatmapResponseTimeTooltip.tsx
+++ b/client/src/Components/common/charts/HeatmapResponseTimeTooltip.tsx
@@ -57,7 +57,8 @@ export const HeatmapResponseTimeTooltip = ({
 						{formatDateWithTz(check?.createdAt, "ddd, MMMM D, YYYY, HH:mm A", uiTimezone)}
 					</Typography>
 					<Typography>
-						{t("common.labels.responseTime")}: {check.originalResponseTime.toFixed()} ms
+						{t("common.labels.responseTime")}:{" "}
+						{check?.originalResponseTime?.toFixed() ?? "-"} ms
 					</Typography>
 					<Typography textTransform={"capitalize"}>
 						Status:{" "}