There are many reasons that could be restricting you from seeing these emails. We will include the major email providers and how you can ensure our emails end up in the right inbox.
Gmail
If you are using Gmail as your email provider you can setup a filter to move our emails to your inbox and prevent them from being blocked or sent to the wrong location.
Creating a Filter - Begin by left-clicking on the down arrow on the area that says “Search mail” at the top of your Gmail inbox. Below the down arrow mentioned above is circled: 
The window that appears after clicking on the down arrow will show an empty window without the “From” address shown in the image below. Type this email address as shown or copy the following: security-no-reply@regpacks.com You have now finished creating a filter, congratulations! Now that this filter has been created, any security tokens received will automatically get sent to your inbox. 
After typing the email shown above in your filter, proceed to clicking “Create Filter”. The next window will show the following options. From these options please checkmark the “Never send it to Spam” and “Always mark it as important” options, then click the “Create Filter” button again. 
Outlook
To add our emails to your safe sender list in Outlook select the Gear icon at the upper-right of your email window. 
The panel that appears just below this will allow you to type text to do a search. Within this text box we will want to enter “safe” and you will see “Safe senders and domains” listed below. Please click the words for “Safe senders and domains” to open the window that will allow you to enter our email address to make sure our security tokens end up in your Inbox. 
Left-click the “+Add” link and enter the same text shown: security-no-reply@regpacks.com Press “Enter” on your keyboard to show the email as a list below the “+Add” to accept the changes. After saving this as a safe domain, select Save at the top right of this window to confirm the changes you have made. Congratulations! Now you will receive security tokens directly to your inbox.
iCloud Mail
Please refer to the Setup rules to filter email in Mail on iCloud.com section on the link below from Apple: https://support.apple.com/guide/icloud/set-up-filtering-rules-mm6b1a3f8a/1.0/icloud/1.0 After clicking Add a Rule the following sections will need to be filled out as such: “If a message… “is from” security-no-reply@regpacks.com “Then” “Move to Folder” “Inbox” Click Done and you are finished! Congratulations! Now the security tokens you receive will automatically be sent to your Inbox.