What can be wrong with a site
A badge on a site names what is wrong with it in two or three words. This page says what each one means, what to do about it, and — the part that matters most — whether it is yours to fix at all.
The same three sentences are in the interface: the site's own page lists them under What needs attention, and hovering a badge in a list shows them too.
What the site's owner can put right
These are yours, or your web person's. They are about the site itself — what it serves, where its name points, how fast it answers.
Server error
The site broke while answering and shows an error page instead of its content.
What to do — Ask whoever maintains the site to read its error log: this is nearly always the site's own software.
401 or 403
The site answers but refuses to show the page: it either asks for a password or denies access outright.
What to do — If the page is protected on purpose, say so and have a public page watched instead; otherwise have the site's access rules looked at.
404
The address being watched answers "page not found", so either the page has moved or the wrong address is being watched.
What to do — Open the address in a browser and, if the page has moved, have the watched address corrected.
Holding page
The address shows a maintenance or coming-soon page instead of the site itself.
What to do — If the site is meant to be live, publish it or ask whoever is building it to finish.
Answers elsewhere
The domain sends visitors to a machine other than the host it is set up on, so what they see is served somewhere else.
What to do — Confirm where the domain is meant to point, and have whoever holds its records correct them.
Slow
The site answers, but takes longer than the time set as acceptable here.
What to do — Ask whoever maintains the site to look at what is slow, which is more often the site itself than the host.
No sitemap
The site offers search engines neither a list of its pages nor the small file they read first, which makes it harder to find.
What to do — Ask whoever maintains the site to publish a sitemap: most site software can produce one.
What the admin puts right
These belong to whoever runs the machine and its hosting panel. Nothing here is yours to fix: report it if it lasts, and it is being watched already.
Certificate invalid
The certificate securing the site has expired or is made out to another name, and visitors are shown a security warning instead of the site.
What to do — Ask the admin to issue a new certificate for this domain.
No answer
Nothing answered within the time allowed, so the site looks down to its visitors.
What to do — Ask the admin if it does not clear by itself within a few minutes: the host may be overloaded or unreachable.
Local mail, MX elsewhere
The domain's mail is handled by another provider while the host still keeps a mailbox for it, so mail the host itself sends to this domain lands in that unused mailbox instead of reaching the real one.
What to do — Ask the admin to switch off the mail service for this domain on the host.
DNS differs
The domain's own name servers and what the rest of the internet sees do not say the same thing, usually because a recent change has not spread everywhere yet.
What to do — Give it a few hours, and tell the admin if the difference is still there.
Zone not delegated
The host keeps a set of records for this name that the domain above never hands over to it, so those records are never used and only mislead.
What to do — Ask the admin to remove the unused records, or to have the name handed over properly.
Certificate expiring
The certificate that makes a visitor's connection to the site secure runs out soon.
What to do — Renewal is normally automatic, so leave it a day and tell the admin if the warning is still there.
No www
The address with www in front of the domain does not lead to this site, so visitors who type it are sent nowhere or to something else.
What to do — Ask the admin to make the www address lead to the site.
No IPv6
The host can be reached over the newer kind of internet address, but the domain publishes none, so visitors on newer networks take a detour to get here.
What to do — Ask the admin to publish the host's newer address for this domain.
SPF
The domain publishes more than one of the records that list who may send mail in its name, and mail systems treat that as invalid.
What to do — Ask the admin to merge them into a single record.
SPF lacks ours
The domain lists who may send mail in its name, and the host it is served from is not in that list, so mail sent from here can be refused.
What to do — Ask the admin to add the host to that list.
No SPF
The domain publishes no record listing who may send mail in its name, so its mail is more likely to be filed as spam.
What to do — Ask the admin to publish one for the domain.
Plan out of sync
The hosting account no longer matches the hosting plan it was sold with, usually because a setting was changed by hand.
What to do — Ask the admin whether to put the account back on its plan or to leave it as it is.
No wildcard
The certificate securing the site covers this one name only, so any other name added under the domain will need a certificate of its own.
What to do — Nothing to do unless a subdomain shows a security warning, and then ask the admin for a certificate that covers it.
What is settled at the registrar
A domain name is rented from a registrar. These are settled there, where the domain was bought, and nowhere else.
Does not resolve
The domain name leads nowhere at all: nothing on the internet can say which machine to reach for it.
What to do — Check with the registrar that the domain is still registered and still names the right name servers.
Registration
The domain's registration itself is in trouble: expired, held, or unknown at the registry.
What to do — Renew the domain where it was bought, or ask that registrar what is holding it.
DNSSEC broken
The domain carries a signature meant to prove its answers are genuine, that signature no longer matches, and careful visitors are refused the site altogether.
What to do — Ask the registrar to update or remove the domain's signing keys.