602 can't connect to the host

EDIT: sorry if I posted this in the wrong sub-forum. Please feel free to move it where it belongs to. This is where I thought it would fit mostly, but I acknowledge that I may have been wrong

Hi there!

I just purchased an email verifier so I can check the 29500 emails the company I'm working for has in CRM (most of them are bad, so we had to check them).

Now, I also purchased 10 shared proxies that I added into the software so I can test the emails (again!!) because I already tested them twice just to find out that the IP I was checking them from is blacklisted. Now, I did take the IP off the blacklists but after doing so and re-checking the emails the IP got on the blacklists again in a matter of hours. So, the only option left for me to be able to accurately check the emails for validity was to acquire proxies, which I did.

Now, when I tested the proxies inside of the software each one of them returned this error message that I have no idea what it means, and which I can't find anything for in Google either:

602 can't connect to the host 'microsoft-com.mail.protection.outlook.com'

So, my question to all of you handsome guys and gals (you ARE handsome, aren't you??) is this: does anybody know what on Earth this message means, and more importantly, can someone give a hint on how to make the software work (with or without proxies, I don't care).

I also need to mention that I already contacted the company that I purchased this email verifying software from, and I'm waiting for a reply from them as we speak. But, asking left and right while you wait doesn't hurt, so here I am

Thanks in advance for any tip / suggestion you can give, and... stay handsome!

Over and out

John