What can the response "Service is temporary unavailable" to a sendMass request mean?

Question

Classmates

Full response from the server:

{"error_code":2,"error_msg":"SERVICE : Service is temporary unavailable.","error_data":null}

It is somehow permanent, that is, it does not look like the API really lies there.
I make a request like this:

curl -v "http://api.ok.ru/fb.do?method=notifications.sendMass&application_key=REAL_APP_KEY&format=json&text=Test-check&expires=20.02.2016+01:39&mask=2147483648&sig=CORRECT_SIGNATURE" -H "Accept: application/json"

sig is correct, otherwise there will be another error.
Many requests also seem to have another error (code 8, FLOOD_BLOCKED) Tell me
, what could be the matter?

Answer 1

Earned. All that I changed in the format parameter was set to JSON (in capital letters) and in expires I changed the date format (it became 2016.02.21 00:00). Most likely business was in expires.