Error establishing a database connection

I recently started a website on a subdomain, than switched it over to my main domain by changing the url in the wordpress login than renamed the folder in ftp. Worked fine. I suspect I may have somehow broken some files I couldn’t see when I deleted the old development subdomain folder under my ftp today?? How can I fix this?

Velvet Blues URL Updater

But that depends on how far along you are. Can you log into WordPress (on your main domain?)
If so, installing that plugin, and then running it should fix a lot of broken urls

Also, you might navigate to and check that everything is set for your main domain.

If you’re comfortable on the command line, we have WP-CLI, which has my absolutely favorite tool ever.

wp search-replace --dry-run

Just remove --dry-run when you’re ready to do it for reals.