Roblox connection error

Guys, I’m having a connection error problem on Roblox and I can’t fix it at all. It’s on my daughter’s PC. I’ve already restarted the modem and nothing. Will I have to format it?

Sorry. There was a problem accessing our servers.

The error that’s appearing on my screen is this one:

erro de conexão roblox

Our internet plan is from Oi and other games and websites work normally.

Is Roblox down or was I banned?

Help, please!