Did this start after upgrading to Sierra?
I'm not sure. I went from El Capitan to Sierra and High Sierra with no wifi issues on my late 2013 13" Pro. I never even heard about the responder issue.Good question, wasn't Sierra when Apple screwed around with mDNSResponder?
Try the latest Sierra update, and make sure iOS is up to date.
If your router maintains logs, look at them before resetting.
Maybe your ISP is having issues with DNS servers, in which case you might try setting DNS on the router manually and use Google or some other public DNS service. Certificate errors and intermittent outages could indicate DNS lookup failures. Certificates for TLS are often validated by comparing the source IP address sending you a certificate with the address obtained from a DNS lookup, if the lookup fails, the certificate may be rejected.
Did this start after upgrading to Sierra?
If you did not make changes to your ISP or networking equipment, I think it is an OS issue. It's a pain but you could try a clean OS install to see if that makes a difference.Thanks for helping, i thought it might be dns issue but how come the dns is not failing in my ipad and my iphone?
No, I have been using sierra for over a year and i am running latest release
If you did not make changes to your ISP or networking equipment, I think it is an OS issue. It's a pain but you could try a clean OS install to see if that makes a difference.