diff --git a/lib/client.js b/lib/client.js
index 3553e8d..1e685fb 100644
--- a/lib/client.js
+++ b/lib/client.js
@@ -790,7 +790,11 @@ export default class Client extends EventTarget {
 		if (!this.isupport.has("MONITOR")) {
 			return 0;
 		}
-		return parseInt(this.isupport.get("MONITOR"), 10);
+		let v = this.isupport.get("MONITOR");
+		if (v === "") {
+			return Infinity;
+		}
+		return parseInt(v, 10);
 	}
 
 	monitor(target) {