Hi Alexis,
Sorry for any inconvenience caused by this issue. And thanks for your clarification.
As Young has mentioned, since you can create Lync Online meeting in Outlook 2013 with this account, the issue should be related to the specific setting in Mac computer. When you mentioned “This issue occurred I asked IT to include my intercall conference number linked with Lync”, do you mean that issue occurred after the IT configured dial-in conference setting for you? If yes, could you try disabling to check if the issue persists? If no, would you mind provide detailed information about “inter call conference”?
Thanks for your time and efforts on this issue.
Best Regards,
Anna Shi