Problem - Error establishing a database connection


#1

Hello. When I try to access my website from my computer I get this message:

Error establishing a database connection

I deleted cookies from my browser and I tried again but it is the same. I also tried another browser but nothing. When I tried with my mobile again the same. 
BUT! When I disconnected from my wifi with my mobile and tried to visit the website with my phone provider without connecting to wifi, it worked normally. 
I dont know what to do as Im not a computer genious.
Thanks a lot for any kind of information

#2

Such error message tells us that there’s something wrong with the database; either the connection, or the credential itself.

But since everyone’s website is working well, then I’m sure the problem is on your credential. Double check its hostname, username, password and database name. The information you needed should be hanging around control panel > MySQL Databases.

…When I disconnected from my wifi with my mobile and tried to visit the website with my phone provider without connecting to wifi, it worked normally. 
Your carrier network provider is a wizard. That’s all I could say.

No srsly, i have no idea how did that happen.

#3
"Error establishing a database connection" is a message generated by WordPress when there is some kind of issue with the database connection.

Normally, this isn't affected by which device or network you use. But it might be that one device is checking our servers and another one is checking your old hosting provider.

If I were you, I'd go to a file manager, edit the wp-config.php for your website and on the line with "WP_DEBUG" change "false" to "true". Then reload the page on the device where the website appeared broken.

If the page shows more information, it means the website is broken with us. The additional information provides a good place to start.

If the error page doesn't change, it means the website is broken with your old host. Which means you can just ignore it and wait for the website to be fully moved over and works everywhere.