We have an issue with one of our websites after installing Magento patches. We use the purchase order payment method to allow customers to pay on account, which until the patches were installed worked as it should.
Since the patches have been installed, clicking on the place order button briefly shows Submitting Order, but then nothing happens. We have tried many things after googling to get this to work, but alas nothing has helped us so far.
Can anyone help is this needs fixing desperately? If anyone is able to help then I can post all the details regarding the website.
Have you reviewed the system.log and exception.log files to review what is the error?