I have been struggling with weird server problems for a while and sometimes I couldn’t notice my server is down. Mostly I notice them when I check my Google Analytics reports because the visitor numbers drops quickly. Finally, I found a free service which checks your web site every 10 minute and sends you a free alert if it is down. They have some pro versions too but free version is neough for me because I only want to get alert when it is down. After sign-up I waited a day, and tested the service, so my server was down for ten minutes, and I got the mail:
Hello,
We found https://teaddict.net to be down.
Reason: Could not connect to server in 25 seconds.
We will notify you again when your website is back.
Basically they try to connect every ten minutes to your website, and their threshold is 25 seconds. After my website was up again, I got the next mail:
Hello,
We found https://teaddict.net to be up again.
Your site was down for 3 minutes.
The service called DownNotifier and can be signed-up from here