500 internal server error when adding key to account

[hongkongkiwi]

When attempting to register my key with my account I get the following:
HTTP/1.1 100 Continue
Expires: Sat, 13 Feb 2016 15:24:35 GMT
Cache-Control: max-age=0, no-cache, no-store
Pragma: no-cache

HTTP/1.1 500 Internal Server Error
Server: nginx
Content-Type: application/problem+json
Content-Length: 53
Replay-Nonce: XXXXX
Expires: Sat, 13 Feb 2016 15:24:36 GMT
Cache-Control: max-age=0, no-cache, no-store
Pragma: no-cache
Date: Sat, 13 Feb 2016 15:24:36 GMT
Connection: close

{"type":"urn:acme:error:serverInternal","status":500}

Any ideas?