It was working fine yesterday but today all of my sites show Error establishing a database connection. If I add a new site, it works fine though. Didn’t find a solution anywhere here. I am working for a client and I’m losing time 
I have this EXACT same issue. I am on a deadline as well. Everything was working normally and now all of a sudden I’m getting this exact same error “Error establishing database connection”. I cannot find the solution to this.
PLEASE HELP!
Okay — it now appears to be working? All I did was restart Local 2 or 3 times, tried opening the site again, and it worked. The Admin button took me straight to the login page. However, as usual, the View Site button, takes me first to a 502 Error page, which requires 2–3 page reloads, then the site appears.
So, I did nothing, it works…I need to push this online ASAP because when something on Local quits working, I have no idea what to do. Admittedly, I’m a web designer and not a network/IT specialist…I wish I was.
Still not working for me 