A few fixes and improvements since the last update, most of them from things you reported. Everything below is live now, and there's nothing to set up.
Regions now take turns (Pro). In the last update, Pro monitors were checked from all three regions every minute. That tripled the traffic to your site, and some hosts' protection didn't like it. Now the regions take turns: your site gets one check a minute, as before, from a different region each time, so it's still watched from US East, Europe and Asia-Pacific. When a check fails, the other regions confirm it straight away before anyone is alerted.
A host slowing the checks down no longer counts as down. Some hosts answer "429 Too Many Requests" when they think they're getting too much traffic. That means "slow down", not "offline", but it was being counted as an outage, and a few of you got false down alerts because of it. A 429 now never counts as down. If a host keeps limiting the checks, that monitor is checked from a single location instead, still every minute.
Every alert email takes you straight to the details. Alert emails now open with a See this alert button that goes to the exact spot on your monitor's page: the incident, the security finding, the visual change or the expiry date. If you're signed out, you sign in and land right there. The link to your own site is still underneath.
Alert emails look like the rest. Down and back-up alerts now use the same design as every other email from the site.
DNS change alerts ignore normal address changes. Big hosts like GitHub and large CDNs rotate between many addresses, which could trigger a "DNS changed" alert every few days. DNS change alerts now remember every address a site has used in the last 30 days and only alert when a genuinely new one shows up. Nameserver and mail server changes alert as before.
Fixed: monitor pages that wouldn't load. On some websites that aren't Flarum forums, the new Security area stopped the rest of the monitor page from showing. That's fixed.
The site reads like a blog now. Updates and extension releases each get their own post, so it's easier to see what's new at a glance.
Thanks to everyone who reported these. Questions or anything that looks off: open a ticket from Support.