Hi John,
What version of OWA are you using? Do you have a Spell Check button in your OWA?
By "I went to the gears icon and checked to make sure spell check is enabled", do you mean you have enabled the "Always check spelling before sending" option?
The spell check function in OWA completely relies on the spell check capabilities of the browser. Since this forum is for general questions and feedback related to Outlook desktop application, I'd recommend you post a new question in Exchange forum for further
assistance:
https://social.technet.microsoft.com/Forums/office/en-US/home?category=exchangeserver
The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction with us. Thank you for
your understanding.
Steve Fan
TechNet Community Support