My accountant does not receive an invitation email, but has from other clients?

Welcome to the QuickBooks Community, @usercuttingedgeiom.

Inviting your accountant in QuickBooks Online (QBO) is easy. However, there are times that the users you invite didn't receive an email invitation. This is sometimes caused by having an incorrect email address, an expired invitation or your accountant's email server blocks incoming emails. To begin fixing this, advise your accountant to check their junk or spam folder first.

If they've seen the email, have them add the @intuit IP address into their mail server so it will recognize emails coming from Intuit. 

However, if your accountant can't still find the invitation, I suggest resend it. Here's how:

1. Navigate to the Settings icon.
2. Click Manage Users.
3. Look for your accountant you need to invite again.
4. Select Resend invite under the Action column.

For more info about the process, see this article: What to do if invited users did not receive your email invitation.

Just in case you'll need an additional person to manage your QBO account, adding them is a breeze. Then, to manage what they can and can't do within your company file, you have the option to restrict their access. 

Post a reply below if you need further assistance inviting your accountant to QBO. I'm always here to lend you a hand. Have a good one.