SMTP Proxies For Mass Emailing

I'm wondering if anyone has any idea on a good way to set up proxies for high email deliverability.

Our aim is to send around 600k emails per month (for 49 companies). Before you say that it's spam, we do comply with CAN-SPAM compliance and our goal is to lower our costs from Outlook.

- We've tried private SMTP servers but of course ran into issues with whitelisted IP addresses.
- We have SendGrid and run into issues with them and they're a bit pricey also..

We're currently looking at https://www.v6proxies.com/mailing-proxies but our main concern is that our domains / emails will get flagged if the emails rotate too frequently as the ISPs will register the rapidness of changing IPs.

IP Royal seemed to address this issue but it seems like it's only for the specific app "Mailbird", which doesn't have the campaign features we need..

Any thoughts??


FROM IP ROYAL'S SITE:

"WHAT ARE MAILBIRD PROXIES?
These are proxy servers designed to change your IP address while using Mailbird. If you use multiple email accounts, you can assign different IPs for each one, so you don't have to worry about your traffic being marked as spam.

WHY DO YOU NEED MAILBIRD PROXIES?
Mailbird proxies are useful when you want to bypass institutional restrictions, add an extra layer of security, or avoid any types of blocks and bans."

Jordanw1630 said:

avoid any types of blocks and bans.

Click to expand...

1) No matter they own entire internet or using enterprise MailerQ they cannot really avoid blocks or bans from email spam.

2) Finding open ports on proxy is really hard and hardly 4 to 5% on services even they allow only long term customers but not customers whom come and destroy their all available node.

3) Coming to V6 their network are already spammed and they are struggling to get de-listed eventually any proxy allows port 25 open ends up in same situation.

Cheers

Figured as much..

The general consensus is a high quality email server is hard to come by..

the proxy should open 22 ports.