Update 23:15pm PST: All API services are back to being operational. Block processing expected to resume in the next 10 minutes, with some catch-up time to follow to process blocks.
At 9:40pm PST we became aware of a set of instances critical to our infrastructure being reported as unreachable by AWS. This has snowballed into increasing delays into answering to API requests and eventually a slowdown in processing blocks. We're actively working on restoring those instances. No user or blockchain data is impacted.