Can you click on something else in the side menu, like Deductions>Deduction Summary? If you use the Find tool (magnifying glass) in the top right, does it allow you to get to another page (ex: T4)?
You can also try clearing your cache or using another browser. This FAQ has instructions on how to clear your cache in many popular browsers: https://turbotax.community.intuit.ca/community/tax-topics/help/how-do-i-clear-my-cache-browsing-history/00/873530
If you are still unable to resolve this issue, please contact our phone support as they will be better able to assist you. This form will help you get the right number: https://support.turbotax.intuit.ca/contact/