We have 2 internet services into our home both from CenturyLink. Our daughter is a Senior Network Security Analyst for a large corporation and she looked at the problem for me. According to her CenturyLink considered the web page not secure on machsupport.com where you enter the Lic. Code from Avidcnc and the PCID code from Mach4 to register the software. I could connect with their homepage without a problem.
We used her iPad connected to Verizon and registered the Mach4 without a problem.
Bob aka MoHawk & Gigawatt
CNCRP Pro4824, Aspire 10, Mach4