I'm using WP 3.4.2 and just upgraded to Newsletter 3.1.0 on my website at http://www.TrustworthyCare.com. Everything is fine after the upgrade EXCEPT that I can no longer access any existing newsletters in the "Newsletters" module in the plugin nor can I create any new newsletters.
The other modules work ok, such as Subscription, Configuration, Subscribers, etc., but the Newsletters module does not.
The problem is this: When I try to edit an existing newsletter, or create a new one, I get a white screen that simply says, "You do not have sufficient permissions to access this page."
This is obviously a pretty big problem.
Now, I also have another website at http://www.AgeAssistance.com where I'm running WordPress 3.5.1 and also just upgraded to Newsletter 3.1.0 there. On that site, I don't have any problem editing existing newsletters nor creating new ones.
Can you suggest a solution? Could it be a problem that the problem site is on WordPress 3.4.2? I have been avoiding updating it to 3.5.1 just because I want to avoid problems that might arise with a core update like that.