Does your error log contain any details (e.g., source IP address) about the failed connection attempts?
I would suggest trying
Allow from 127 ::1 your.ip.v4.addr your:ip:v6::addr. Don't use host names unless you have to, as Apache performs
forward and reverse DNS queries to verify the address, taking extra time and effort.
127 - While most local networking uses 127.0.0.1, technically any address in the 127.0.0.0/8 subnet could be used.
::1 - If you're using IPv6, this is the address used for local networking.
your.ip.v4.addr - The application trying to access Apache may be doing so using the public IP address, in which case the source will be the same IP address, not 127.0.0.1.
your:ip:v6::addr - Same as above, for IPv6.