My site was working fine for the last year until I made the switch to Express Checkout from Unicode Systems. I paid the $ and the extension didn't work, only brought the site to a round of errors. I unistalled the extension and everything seemed to be fine until I noticed that you cannot place an order when logged in as a registered user. There is no problem with guests checking out only those who are logged in. Please, any help is much appreciated.
Here is the site:
Thank you in advance for any insight or help.
The best idea is to connect with Unicode extension provider for that issue may they will guide you Or hire Magento developer