ios - Heroku sporadically returns "hostname" not found -

i'm creating ios app uses rails api backend on heroku. periodically (one every 20 api calls), heroku cannot found. following nserror returned:

error domain=nsurlerrordomain code=-1003 "a server specified hostname not found." userinfo=0x755ce00 {nserrorfailingurlstringkey=https://xxx.herokuapp.com/api/v1/matchups, nserrorfailingurlkey=https://xxx.herokuapp.com/api/v1/matchups, nslocalizeddescription=a server specified hostname not found., nsunderlyingerror=0x71ca730 "a server specified hostname not found." 

seems dns issue on network iphone/ipad connected. sure, try of following:

1) change host name ip address instead of string hostname, , add host: header http request.

2) if (1) hard, set iphone's dns pc on lan, , install dns server on pc, , serve @ least specific address directly pc (don't recurse domain).