It seems that our security cookie is never being issued by your website. It may have to do with your WordFence settings or some other plugin which has to do with cookies or security.
If you can arrange me an admin account (a new account which you will delete afterwards) with which i can look into your WordPress installation, that would help fixing this greatly.
If that’s ok, please PM me through the forum, I will give you an email address for which to create this user and send the credentials to. Please never give any credentials to anyone else.
It will take a few days to go through this (not including the weekend), after which i will let you know so you can delete that account.