Just tried to purchase gas, debit card declined. Called Citi and support said they currently could not access user account info and to call back in 30 minutes. They couldn't even verify social security numbers.
I wonder if it's a hack?
- it's a planned outage of some internal system for an upgrade/patching/DR exercise
- it's an unplanned outage of some internal system because some planned change to something it depends on went awry and had an unanticipated impact
- it's an unplanned outage of some internal system because some key component drifted into a bad state (e.g. database server ran out of disk / unique identifiers, call centre line to data centre was attacked by a rogue backhoe)
To make a guess, they've probably got 10-100 key services or dependencies that need to be healthy for this function to work and they're probably running 1,000-10,000 different software platforms internally (not instances but different software applications).