Mac Outlook Send Button Gray Out

Hi there,

I cancelled one of the scheduled email, and now, my mac outlook send button grayed out, it's no longer working. I found many thread on this subject, don't think that's fixed yet.

Does anyone have experience resolving it? 

System: Mac Air, M2, 2022 (Mac OS 14.1.1 (23B81)

Outlook: 16.68