Troubleshooting
Fix common issues with our step-by-step troubleshooting guides and solutions.
29 articles in this category
Website Not Loading
Diagnose and fix issues when your website is not accessible.
500 Internal Server Error
Common causes and solutions for 500 server errors.
Email Delivery Issues
Fix problems with sending or receiving emails.
DNS Propagation Delay
Understanding DNS propagation and how long it takes.
Connection reset during an upload
Small files work, large ones die part-way with no error page. A timeout is cutting the connection while the file is still moving.
A cron job that never runs
It works when you type it and does nothing on a schedule. Four reasons, and the one line that shows you which.
403 Forbidden
The server found the file and refused to serve it. Four reasons, in the order they are worth checking.
413 Request Entity Too Large
The upload was rejected before your application saw it. Three limits have to agree, and people usually raise only one.
429 Too Many Requests
Something is counting your requests and has decided there are too many. Finding out what is counting is most of the fix.
502 Bad Gateway
What a 502 actually means, the four things that cause it on an Nginx server, and how to tell which one you have.
503 Service Unavailable
Either the server is deliberately refusing work, or it has run out of the capacity to accept it. The two look identical and are fixed differently.
504 Gateway Timeout
The request was still running when Nginx gave up waiting. How to find what it was waiting for, and why raising the timeout is rarely the answer.
Reading your own error log
Four logs, four different questions. Which one answers yours, and how to find the line that matters in a file with a million lines.
Fonts blocked by CORS
The font file returns 200 and the text still renders in a fallback. Fonts are fetched under a rule that images are not.
FTP connects but shows nothing
The login worked, so the credentials are right. An empty listing is almost always one of three things, and none of them is the password.
Which status code means what
The number tells you whose problem it is before you read a single log line. A short map of the ones that actually appear.
The site loads but the images do not
HTML arrives, pictures do not. The network panel names the cause in one column, and there are only four.
Everything is fine but the customer says it is down
You can load the site. They cannot. Before doubting them, check the five things that are true for one visitor and not another.
The padlock is missing on one page
Every other page is secure and one is not. The certificate is fine - something on that page is being loaded over http.
Permission denied on a file you own
ls says the file is yours and writable, and the write still fails. Four causes, and the command that identifies each.
Seeing PHP errors without showing them to visitors
display_errors on a live site leaks your paths and your database name. The log has the same information and shows it to nobody.
A redirect loop
Two rules each undoing the other. How to see the whole chain in one command and find which pair is fighting.
The domain still points at the old server
You changed the record hours ago and the old site is still there. Find out whether it is DNS, a cache, or the record you did not change.
Logged out every few minutes
The session is being deleted, or never saved, or looked for in the wrong place. Three causes with different fixes.
The site will not load - where the fault is
Four commands that place the fault at DNS, the network, the web server or the application, before you change anything.
Slow admin, fast front end
The public site flies and the dashboard crawls. That difference is a clue, not a coincidence: the cache is only serving one of them.
SPF, DKIM and DMARC failures
Three DNS records decide whether your mail is delivered. What each one proves, and the mistakes that break them.
A blank white page
PHP stopped and said nothing. How to make it tell you what happened, without showing the error to your visitors.
It works on wifi but not on mobile data
The same phone, the same page, two networks and two results. Almost always DNS, IPv6, or a certificate chain.