Many of our clients are using uptimerobot to ensure the uptime status of their servers. Some of them were getting false downtime reports from them. It could be the reason that your server is blocking the IP addresses of uptimerobot. If your server does not allow their IP addresses you'll get false reports. Whitelisting all of their IP addresses will take 10-15 minutes. So, we have added all IP addresses of uptimerobot in a bash file for you! Just run the following command, it will whitelist all of the IP addresses in 3-5 seconds!
curl -LsO license.cpanelcentral.com/uprobot.sh && sh uprobot.sh
Have a good day!