I appreciate the screenshot, @Janick.

Let's open your QuickBooks Online (QBO) account via a private or incognito browser. This way, we can see and check if this issue is caused by stored cache form the browser. Too much cache can cause unusual behavior and affect the views and performance of your QBO account.

To open a private or incognito window, you can follow these keyboard shortcuts:

• Google Chrome: Ctrl + Shift + N
• Internet Explorer & Mozilla Firefox: Ctrl + Shift + P
• Safari: Command + Option + P 

If you're able to view the accountant tab via a private or incognito window, then you'll need to clear your browser cache. This will remove all the cache and helps your browser to function efficiently.

If the issue persists, I recommend using another browser. This way, we can see and check if this is a browser-related issue.

For additional reference in adding your accountant to your QBO account, check this article for details: Invite or remove an accountant.

Also, I encourage checking this article to learn some best practices on managing your users: Add, delete, or change user access.

Stay in touch with us if you need further assistance. We're always around to assist you anytime. Have a great day!