If you ever get the “Error establishing connection to database.” or “Cannot connect to database.” there could be some possible reasons.
1. Check if MySQL is running
Login to your hosting panel using “admin” user.
Check if the database server (MySQL) is running. If not then start/restart.
server > MySQL > start/restart
IF MySQL does not start/restart
Check if your disk is full.
server > show: CPU/ MEM / NET / DISK
2. Check if your database details are correct.
Download your database config file from FTP.
You can edit the password from the hosting panel.
user > webuser > login as webuser > db > your_db > edit
Type the password then save.