Arbitrum (layer-2 on Ethereum) hasn't process a single transaction in more then 2 hours now and it scares me

I am a big believer in layer-2 roll-ups for Ethereum scalability, so pretty much all my funds are on Arbitrum. I woke up earlier then usual this morning to do some transactions while the gas fees are low, but I couldn't connect my MetaMask wallet to Arbitrum on any DEX or dApp.

I went to Arbiscan, and what I saw scared me : the last transaction was processed more then 2 hours ago.

There is no announcement on their Twitter or subreddit, so I went to their Discord server. They had this message :

Hello - we are aware of some issues with the network. We are investigating and will post an update here once we have one.

I am worried, because right now I can't do the transactions I want to do, and that's a weird thing to say in a supposedly permissionless, censorship-resistant environement. There is no explanation whatsoever about what happened ; I guess it has to do with the high volume of transactions during the crash, but I really don't know.

I was using Arbitrum because I thought it was reliable and secure. But now my confidence is shaken.

Anyone has any idea what could be happening? Does it scare you too?

EDIT (3:49 PM EST.) : Looks like the problem was with their sequencer, and it is now back online. Transactions are going through smoothly. Phew, what a ride it has been! Glad we are back in business.

EDIT #2 : Here is a follow-up the the team just released. They are very transparent about what happened, and that puts my mind at ease.