Trend Micro Web Security conflicts with Network Solutions

1) Network Solutions - is a Domain Registrant, not an ESP (Email Service Provider).

If they do provide ESP services, I'd choose some other company, like https://MailGun.com as a first test.

2) Trend Micros Hosted Web Security - Best to just check reviews for this product. Seems like this provide fairly standard features. Best to do your own research to determine if this software is acceptable or you'd prefer software from a more established (larger capitalization) company.

3) As soon as we adjust the mx and txt records as per Trend Micro's instructions I can no longer receive emails.

This sounds like a horrible idea. I suppose they expect you to pass all your mail through their system.

Problem is, when their system is slow/down, then so is all your email.

To work problems related to Trend Micro, you'll have to open a support ticket with their company, as only they know their tech + have access to their logs, so they're the only people who can answer your questions.

4) 503 you must authenticate first

Almost surely means you're attempting to connect your inflowing mail to port 587, rather than port 25, which simply won't work.

See #3 for how to debug this problem with Trend Micro.

I hear what you are saying about passing emails through another server but since this server is scanning for malware wouldn't this be one reason to do this? We are a small company so volume is not a problem. In today's world I would think it would be better to be safe than sorry.