Hello there, @martymainiak.
It's nice to see you here in the Community. I'm here to share some information about inviting an accountant in your QuickBooks Online (QBO).
Sending an email invites to your accountant will only take a few minutes. The inability to receive email user invites is typically due to an expired invitation or a blocking mechanism on your accountant's mail server. Before we perform any troubleshooting, I recommend having your accountant check their junk or spam folder.
If they're able to see the email, have them add @intuit IP address into their mail server. This is to allow our emails to pass through. You can check out this article for further guidance: How to set up your email account to receive messages from Intuit.
On the other hand, if they're still unable to receive the email, you can resend the invitation. The process depends on the Manage Users interface you have.
To check which view you have:
1. Go to your Gear icon, then select Manage Users.
2. Scroll up to your browser's address bar.
3. If the link/URL ends in usermgt, you have the new interface.
4. If it ends with legacyusermgt, you're looking at the old interface.
Please see the sample screenshot below.
Once you're able to determine which interface to have in your QBO, refer to the steps under the Resend an invitation email section of this article: Invited users did not receive the email invitation for QuickBooks Online.
That's it. Please let me know how it goes by leaving a comment below. I'd be glad to answer should you have any follow up questions. Have a great day!