So what's happening is your email provider (spectrum) is returning emails to us as a "soft bounce". That means they're letting us know that the emails we're sending you may not be delivered. When our system receives X number of soft bounces from an email address, your account is put into an "invalid email" status. This is to keep our mail server reputation clean because if we continue sending emails to email addresses that are bounced, our mail server IP could get added to block lists which would prevent us from being able to send any emails out.
They're blocking the emails already because they say we're opening too many connections with (sending to many emails to) their server in a short period of time. In other words, they think we're spamming them because we're sending too many emails in a short period of time. I'm assuming that anyone with a spectrum email address, across all of my sites, is having the same issue and you're just the first person to bring it up. Either that, or perhaps you're the only one using spectrum as an email provider.
All that said, there's really nothing that we can do to prevent this from happening. The only thing I could suggest is to change your email address to a different email provider. I know that's not ideal but unless spectrum will whitelist our mail server IP address (not likely going to happen), they'll just continue to send those emails back as bounces and our system will continue marking your account as "email invalid" after you've reached the threshold for soft bounced emails.
