Over the past six months there have been around 4 or 5 cases where websites have stopped working. This can invoke panic if you have never seen it before. There will be a white screen and some short message on it which will not mean a lot to you.
Firstly do not panic
Your website is still there, but cannot run. WordPress introduced some measures around six months ago which ran some diagnostic and other tests and reported on the health of the website. It is since this change some sites have failed, probably because one of the trapping mechanisms trying to identify problems has kicked in.
Generally what has happened is the website may have been upgrading itself, the upgrade has caused a temporary conflict, and this or some related event has caused it to crash. What you see is the white screen. It can sometimes be falsely triggered by security plugins.
How bad is it?
The first thing to check is whether you can still log in to the site. Try to login as an administrator. If you can get into the site, there may be a warning message there. If the problem is down to a plugin (it normally is) try turning some of them off and see if the website returns. If the site does return, delete the broken plugin, and try reinstalling it.
If you cannot login and have access to the hosting
Normally the way I have to handle these problems is to log into the control panel, use a file manager to locate the plugin directory for the website. I then work my way down the list renaming the directories by adding some text at the end of the directory name. For example if the directory was called wordfence, I will rename it wordfence-off. When I do this, the plugin can no longer load. If it was the one causing the problem, then the site will return.
I would then delete the plugin and reinstall the latest version, that normally fixes it.
Can’t fix it?
If you cannot resolve the problem, send me a message, better still call me on the phone, and I will take a look as a priority. But you may find you can resolve this yourself.
Why?
I use a very limited set of proven plugins across the websites I build. They are all well maintained, and if a problem exists, and I can identify it (usually takes around 30 mins), so far removing and reinstalling them has resolved the problem. You may however have added in your own selection of plugins. Not all plugins are equal. Yours may be causing the problem.
If you are stuck, and have refreshed your browser, or tried a different browser and get the same result alert me immediately and I will try to get it resolved for you quickly provided I am near a computer.
If the worst happens
We always have a weekly backup we can rely on for website recovery if we run into a problem that cannot be resolved.