Unable to edit newsletters after upgrade

I’ve been using Mailpoet for a while and sent out a monthly newsletter. I’ve not sent one in a couple of months, but tried to send one a few weeks ago and noticed I can’t.

The newsletter appears as a recipient would see it without any edit options. I can also no longer edit any of the sections.

I’ve tried to create a new newsletter and get the same results.

Uninstalling and reinstalling MailPoet has no effect.