Hi Clyde,
Before moving on, I’d like to know the following information for clarifying:
1. What subscription of Office 365 are you using?
2. Can you access the website before paying for the subscription?
3. Have you ever changed the website’s URL with your custom domain?
As far as I know, the trial should last 30 days, and then it will get into the 60-days grace period. After that, your account will be deleted.
If your account can be accessed successfully now, I recommend you to check the website URL in portal, and then try to access it again. If the issue persists, could you please capture the error messages and then post them here for further troubleshooting?
Thanks,
Nancy Xie