Hello and welcome to DigitalOcean.

"Why doesn't Digital Ocean return an A record for hotmail.com?"
Easy as 1+1, hotmail.com is hosted by Microsoft and uses their Nameserver.

"Is Digital Ocean's DNS working?"
YES

Watch this Video !!!
What is DNS

PS: If you understand it, click on the hearth to show me some love (i really need it, had a bad day :-() :-).

Sorry, I missed the first part of the question.....when I tried a "dig hotmail.com" the response I got was the SOA data and no 'A' record.

I think either Microsoft or Digital Ocean is being flaky. Anyway it is all working again now. Don't know why it stopped but it is back

$ dig hotmail.com

; <<>> DiG 9.9.5-3ubuntu0.3-Ubuntu <<>> hotmail.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13245
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 13, ADDITIONAL: 16

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;hotmail.com.           IN  A

;; ANSWER SECTION:
hotmail.com.        2042    IN  A   157.56.172.28
hotmail.com.        2042    IN  A   65.55.77.28
hotmail.com.        2042    IN  A   157.55.152.112
hotmail.com.        2042    IN  A   65.55.85.12

I notice this when my email fails:

status=bounced (Host or domain name not found. Name service error for name=hotmail.com type=A: Host found but no data record of requested type)

And this seems to happen on and off. Looking at google I see that a few others have reported a similar thing with hotmail so maybe its at their end, but I would have guess Digital Ocean would have cached responses?

Sorry to say it, but I and DigitalOcean can't help you with this problem.

DigitalOcean is not responsible for problems of the Microsoft DNS.

Did you actually watched the Video? I am pretty sure that you don't understand how DNS works.

DigitalOcean has no cached response, your OS is responsible for that, see :

'''
But using a different server:
'''
# dig @ns1.msft.net hotmail.com

; <<>> DiG 9.9.5-3ubuntu0.3-Ubuntu <<>> @ns1.msft.net hotmail.com
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 45461
;; flags: qr aa rd; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4000
;; QUESTION SECTION:
;hotmail.com.           IN  A

;; ANSWER SECTION:
hotmail.com.        3600    IN  A   65.55.77.28
hotmail.com.        3600    IN  A   65.55.85.12
hotmail.com.        3600    IN  A   157.56.172.28
hotmail.com.        3600    IN  A   157.55.152.112
'''

PS: you need to use

dig hotmail.com

with

dig @ns2.digitalocean.com hotmail.com

you ask ns2.digitalocean.com where hotmail.com is located, but ns2.digitalocean.com doesn't know where it is.

The Nameserver who is responsible for hotmail.com is ns1.msft.net

Thanks, I agree that my original 'dig @ns2.digitalocean.com hotmail.com' was a silly idea. That was a mistake.

Before that I had tried "dig hotmail.com" and that was the example I intended to use to show the lack of response. I accept that it was at Microsoft's end that I wasn't getting a response - it seems it wasn't the first time it had happened.

Anyway all good now, and next time I will know to wait and check Microsoft.

ps I'm surprised that Digital Ocean doesn't do any caching. Most busy DNS servers use caching otherwise the world would be full of hotmail.com and google.com going up to root each time....even my own DNS server does caching. Also makes you wonder about the TTL value in the A record query response doesn't it.

pps its hard to reply to these questions without being patronising isn't it