I can't access my dropbox. The email is no longer active. How can I access dropbox

I'm sorry to hear about your situation. To the best of my knowledge, if you had access to the associated email, you could attempt a password reset. This would send a reset link to the email if the Dropbox account still exists. However, since you don't have access to the email, this option isn't available to you. Additionally, it's worth noting that Dropbox accounts left idle for more than a year are often deleted due to inactivity, as per my information.
Regrettably, without access to the email, regaining access to the Dropbox account is not possible.

Again I say that you might consider contacting the email service provider to see if they can reinstate your email address, even temporarily.