::1 is IPv6.
127.0.0.1 is IPv4.
::1 is IPv6
127.0.0.1 is IPv4
I guess you disabled IPv6 in between tests?
The former, "::1" is IPv6 compressed syntax for the localhost. It is equivalent to 127.0.0.1. Did you disable IPv6 support in your OS or network adapter? Maybe that's why it stopped working.