amazon web services - AWS EC2 response not received on the client side -

i using t2.micro instance serve requests front-end hosted on s3. interestingly enough, 90% of users can response. however, there 10% can't response back. of these users in enterprise environment.

i had chance check 1 of friend's chrome dev tool (using on our front-end) , saw weird behaviour no response sent back. then, sent json request endpoint directly. there onwards, started work. recently, potential adopter enterprise tried our prototype , same thing happened again. time, wasn't lucky , got lecturing user. :(

i tried searching online tons of possibility. can come 2: ( ) firewall blocks response sending ec2 addresses (i not using route 51 yet attach our domain name yet) ( ii ) there sort of routing issues going on

if think these reasons what's happening, please let me know can fix them. otherwise, debugging steps can take?

you can find our site here: http://resohub.s3-website-us-east-1.amazonaws.com/ , test if have same problem.

updates:

(a) typo in t1.micro. using t2.micro.

(b) have low request/sec.

(c) know isn't application problem 2 reasons. one, use own web app on daily basis. had never given me issues. two, have server logs , not see errors @ all. nonetheless, going add more logging messages in case.

(d) know once user cannot received response server @ time t, not able receive response there onwards. emphasize, in 1 case, able solve issue asking friend make direct request endpoint.

(e) eat own dog food every day. have seen being slow not case users tell me results never being returned. problem 10% of user face results never being returned.

do see requests (in server logs)? have logs server side?

having guess tell at: http://docs.aws.amazon.com/awsec2/latest/userguide/t2-instances.html

section cpu credits. hunch @ point but: if don't use while works fine. if start putting under heavy load start experiencing this.