You have a report that has an email subscription to send you results from a report in Marketo. When you click on a link for results, you get a 404 error.
A possible reason why this is happening is because the date range for the results in your email is outside the current date range for the report.
For example, you have a report that runs for the past 7 days. The email has data from 1st to 7th. If you run the report now, you will get data from the 8th to the 14th. Since the current date range of the report is outside of report date range from your email, the link in email will not work.
However, if you change the date range on the report to run from the 1st to 14th, then the link in the email should now work.