Thanks for your posting here.
I understand that you have wait for at least 24 hours, however, Setting up Exchange Online …this may take a few minutes still persists.
In general, this issue occurs if the service has not finished provisioning for the company. So, would you please directly type http://mail.office365.com in your web browser and enter your Office 365 credential, to see if you can access OWA successfully?
If the issue persists, it also recommends removing the Exchange Online license and then re-assign. Please wait for at least 15 minutes before reassign the license.
Thanks,
Grace Shi
