How to clear DNS cache ?

Question

We are using XG230 firewall with latest firmware. We are web development company, we frequently update pages and DNS for our clients. But these changes not update for the users under firewall proxy rules. At same time, it is working fine with users without proxy and mobile networks. 
 
 How do I fix this issue ? 
 Done: Restarted all services including DNS and proxy. Restarted complete firewall. But still issue not fixed.

Christian Lempa · Answer

This workaround should clear the DNS cache: 
 1. Go to Configure -> Network -> DNS 
 2. Click "Apply" on the DNS configuration (you don't need to change anything) 
 3. Wait a few seconds until dns service is restarted