Open the failing run (from Runs or View Runs on the monitor card). The plain-language outcome is at the top; the technical detail beneath it usually contains one of the messages below.
"Selector could not be found"
The element the monitor looks for isn't on the page any more. Usually the site's layout or markup changed.
Fix: edit the monitor, click Pick visually next to the selector, and choose the element again on the fresh preview.
"Selector matches N elements"
The selector is ambiguous — it matches several elements. Common on news and listing sites that reuse the same class names everywhere.
If the monitor was set up with the visual picker it also saved the element's position, and it falls back to that automatically. To fix it for good: edit the monitor, open the picker, and use Track this spot mode, which follows the position rather than the selector.
"Baseline captured"
Not a failure. A change monitor's first run only records the baseline; comparisons start on the second run. Click Run Now once more if you want to see a comparison straight away.
"Could not be captured reliably" / overlay / placeholder
A cookie banner, GDPR consent wall, paywall, or interstitial ad covered the content. Simrix tries to dismiss these automatically and learns each site's pattern over time. Run the monitor manually a few times; if it keeps failing, pick a region that sits below the overlay area, or contact support with the URL.
A workflow monitor fails but the site looks fine
Read the Final success check in run detail — it says exactly what was expected. Common causes:
- the expected text was reworded or moved
- the page redirected somewhere unexpected (check the final URL on the run)
- the element loads late and the check ran before it appeared
- the site blocks automated browsers or shows a different page to them
Open the site in a private browser window and compare with the run's screenshot.
A change monitor flags changes constantly
Something inside the captured area changes on every visit: rotating ads, a "trending" panel, a timestamp, a random product. Switch from Full page to Selected region and pick an area that excludes it. If the noise is images only, the Fast preset (text-only) ignores them.
Runs take a long time
Simrix waits for the page to finish loading and settle before capturing. Media-heavy sites can take twenty seconds or more. This is normal and doesn't affect the result. If a run exceeds the limit it fails with a timeout — that's the site being slow, not the monitor.
"Monthly run limit reached"
Your workspace has used its plan's run allowance for the month. Monitoring pauses until the next billing month or an upgrade. See Billing and plans. Reducing frequency on monitors that don't need it (a policy page rarely needs checking every 15 minutes) makes the allowance go much further.
"Verify your email before performing this action"
Password-based accounts need a verified email before creating sites or monitors, running monitors, or changing billing and team settings. Use the banner on the dashboard to resend the verification link, then check your inbox.
A monitor isn't running on schedule
Check the card: a paused monitor (grey, Resume button) doesn't run. Otherwise, confirm the workspace isn't over its run allowance and that billing is in good standing under Account → Billing — a past-due workspace keeps running for a grace period, then pauses.
Still stuck?
Ask MonitorBot (the chat button at the bottom right) — it can see your monitors and recent runs and often spots the cause. If it can't, it can open a support ticket for you with the conversation attached, or file one yourself under Account → Support.