diff --git a/FAQ.md b/FAQ.md
index ae3973a..83508ff 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -594,6 +594,10 @@ you can also add `proxy=http://username:password@example.com:8080` to .env file
 
 About how to set up http proxy server, please check https://github.com/rustdesk/rustdesk/wiki/Set-up-http-proxy-server
 
+# How often does `Pro` check license?
+
+It pings rustdesk.com on port 443 (outbound) daily. If the ping fails, it retries every minute until it succeeds or until 7 days have passed.
+
 # The connection is interrupted every 10-15 seconds
 
 Check `C:\Windows\ServiceProfiles\LocalService\AppData\Roaming\RustDesk\log\server\RustDesk_rCURRENT.log`, if there is something as below.