The rate limiter has not changed, but over overall traffic has and this causes more 503 errors to be thrown. At peak times like last night we’re hitting our 30mbit/s committed traffic limit. We could buy more bandwidth, but then we would likely need to buy more servers to handle the capacity.
We’re currently trying to get away from operating our own servers and instead rent servers from some other provider. In order to do that we need to finish establishing our EU presence (a few weeks more, sadly) and then we need to select a new provider and negotiate a new arrangement with them.
Then we can begin the process of migrating across the pond, which is also going to be an incredible amount of work. Fortunately @zas has been making a lot of progress on this. For now, we just need to bear with the current situation. 