Updating this thread. I ended up setting up the squid.conf file with the following config to get it to work.

First, at the top of the localnet lines-

acl localnet src 205.205.205.1/32

Then, I added the only domains that I wanted to provide access to. This whitelisted them.

acl GOOD dstdomain .google.com acl Good dstdomain .domain.ca

Followed by, the allow and deny lines

http_access allow GOOD http_access deny all

Finally, "uncommenting" the Safe ports/services for 80 and 443.

I was able to fix the issue with the following lines on Apache as Reverse Proxy

ProxyPass /soap/v1/ https://api.authorize.net/soap/v1/ ProxyPassReverse /soap/v1/ https://api.authorize.net/soap/v1/

I assume this can also be done on Ngnix as well. So I will find out.