Hi, JoanneNZ14
Thanks for your post, and welcome to the MYOB Community Forum.
If the error message says that the email address already exists, please check the user access window to see if any user added has the same email address of the advisor. To do this, go to Setup > User Access. Check each user ID and the email address entered. If the same email address was entered, you can delete the existing if it's no longer needed and then add the advisor again. More information regarding this can be found in the Help Article: Invite a user to an online file.
Feel free to post again anytime if you require further assistance.
If my response has answered your inquiry, please click "Accept as Solution" to assist other users in finding this information.
Best regards,
Doreen