I finally resolved this issue. Turns out that it's an odd setup that Network Solutions has for sending emails.
This issue with Network Solutions that literally took 3 months to resolve. Yes, 3 MONTHS to resolve the issue. 2 months of that was working with my web host to figure out; neither the best techs at HostDime Global nor did the Network Solutions support techs knew what was causing the issue. Of course they both blamed each other for several months.
Whenever you purchase domain names through NameJet, those domain names are automatically put into a "random" Network Solutions account that they create for you. You're told the username, but you need to use the password reset function of Network Solutions to reset the password. No big deal, right?
Well, it turns out, that for me, that password reset function didn't work. It apparently was sending an email, but that email wasn't being received. I actually confirmed it with my web host, and the emails weren't even getting to my server. We (me and the host) checked the email logs and they were not getting to my server.
After 4 different support tickets set up at Network Solutions, Tweeting at them, calling, chatting, etc., those tickets all ended up being closed by Netsol without my knowledge. I'd call back in or message them for a status, and they had closed the ticket with no resolution whatsoever. Actually, one support closed a ticket because "my email address didn't exist". This despite the fact that they were sending emails to me about domain renewals and, while on the phone with them, they sent a 'verification pin number' via email and I received those emails just fine. So they can send me email for pin verification, but never a password reset email. Huh.
So, escalating it once again, a few more support tickets, I finally got it to a point where I was emailing back and forth (with the same email address) with someone in Corporate (Newfold). He was unable to resolve the issue.
Here I am, today, again trying to see the status since I haven't heard anything from Network Solutions.
It was mentioned that there was an issue with the MX record, and apparently it had an underscore the MX record. It turns out that Cloudflare obfuscates the true host mail record. Long story short, if you use Cloudflare for your DNS, then there's a technical way that you have to set up the mail records (you need an additional A record for mail, and that has to point to your IP address that handles mail). Otherwise, Cloudflare obfuscates, and you actually won't be getting all of your email. Most will go through, enough so you won't notice an issue. However, I've learned through all of this that certain companies (such as Network Solutions) won't get delivered.
Bottom line? If you're using Cloudflare for DNS, and that domain uses email, there's a good chance they're obfuscating your mail records. If that's the case, PM me and I can tell you how to fix this.
*tl;dr* I wasn't getting certain emails from Network Solutions because their wacky email setup at their company won't deliver emails to domains whose email records are being obfuscated to protect you from getting spam email. Check your MX records (email records) on your domain to make sure it's not being obfuscated.
