It will happen to everyone sooner or later, if you are using the capacities of your site. You will be doing an update, and maybe in the middle of the update you accidentally click a button, or do something else – and then you discover your wordpress site is stuck in maintenance mode.
Your beautiful site is replaced with a white screen and ugly black text. It says it will be back in a minute, but it’s been ten. Now fifteen. Help?
There’s no button you can push inside wordpress to fix this. You have to get manual.
You need to use an FTP tool like filezilla,. or the file manager in your hosting control panel, and get into the home or root directory of your site, and find there a small file called .maintenance.
That’s dot maintenance. .maintenance
Delete that file. That’s right, just wipe it out, select it, delete it. Are you in doubt? Okay then, rename it to something like .idontknowifishoulddeletethis-maintenance
Happy? You could have just deleted it, but this is good too.
Now, reload your website. The reload may take longer than usual.
Hey look, your site’s back. Cool, right?