Error establishing database connection when accessed from another network

Hi!

My website, https://pplh.ipb.ac.id, is a website installed on a campus server. I use Monday theme from Yootheme. It is normal if I access it by using the campus network. But when I try to access it from another network, I got error establishing database.

All of the credentials in the wp-config are correct.

If I do access the wp-admin (from the outside network), I got the database need to be repaired. And after I do the repair, I got wp-options is not okay. Only wp-options table, the other are okay.

I checked the wp-options table, and it is there. Everything is okay

So, what is wrong?