Need help with mysql and database

Hi ,

first I am green at this skills.

so I don't know how to do and what next to do

I have two websites in my lindoe.

1GB RAM

1CPU Core

24GB SSD Storage

2TB Transfer

40Gbit Network In

125Mbit Network Out

for two normal websites, i think the space is enough.

However, I often got a problem, every evening here the websites mysql will stop running automatically.

the websites are working fine, but I could not login in the wp-admin, that page will shows the " error establshing a database connection, the username and passward information in your wp-config.php file is incorrect" something like that.

but I doule check those information, it is correct.

Help, pls guide me how to do next? what should I do?