A lot of websites are being under DDoS attack at the moment, just like this forum, as an example, it is impossible to post or just to search on the forum because it is incredible slow.
bitfinex getting hammered by both DDoS attacks and customer spam for last few days.
It is fine, bittrex should be doing the same right now, but no. They are getting thousands or even dozens of thousands of tickets per day, and they are not even replying a single one a day, at least, bitfinex is a little bit honest (not honest at all, but just a little)
Seems like their system isn't good enough to handle that much of an attention, so they shutting down some of the micro-services (like depositing) to make sure important parts (matchmaking/accounting) will survive the hassle.
Do you really think that there are exchanges that are caplable of having more than one million of requests per second? it is impossible, not even the NASA has the ability to do it.
Even though they claimed they use engine capable of digesting 1 000 000+ requests per second, evidently it is not.