The "Let's Go" link does not work for the new user. It states that the link is invalid. What do I do?

It's nice to see you here in the Community, RaeLauren13.

I recognize the importance of accepting your boss's invitation to be a new user in their QuickBooks Online (QBO) company. Allow me to provide some information about your concern.

Currently, there's an investigation about customers getting an error message while accepting an invitation. The email client can only handle URLs under a specific limit. Rest assured, our product engineers are determined to check the root cause of this issue and are working diligently to deploy a permanent resolution.

As a workaround, have your boss resend the invite and open it from a mobile device or a web client. From there, accept the invitation.

Additionally, I recommend contacting our phone or chat support to be added to the affected users list. To be notified of the updates through email, you can provide this investigation number (INV-91437) for easy tracking.

For more info, check this article on adding and managing users in QBO: Add and manage users in QuickBooks Online.

For future use, here's a guide on the different options for user permissions: User roles and access rights in QuickBooks Online.

Please keep in touch if you have further concerns about accepting invitations in QuickBooks. I'm happy to assist you further. Keep safe!