I am unable to open an outlook email that is in my task inbox on my I-pad. Is there a way to do it?
Unfortunately, that's not possible. These "mails" are local links to a specific email with a specific ID that only Outlook can understand and find if you click on such link in Outlook.
If you don't use this option and would rather prefer to be able to read the whole mail anywhere, then instead of linking tasks to mails through Outlook, you can send/forward them to Todoist.
For more information about this option, go to todoist.com right-click on a project and choose "Email tasks to this project" from the drop-down menu.