Checkout Login Loop

I was having a similar issue in version 2.2.  This returned to login when I made a administration change and saved. The fix was to move servers.  My original ecommerce server did not provide enough memory. I was advise and move on to a new server. My ISP Appliedi identified the issue.  Possible worth checking with your ISP.

OK, It happened again and I think I know the cause!  If a person has the Guest role no matter what other role they have this causes them not to be able to checkout.  Simply remove the Guest role and it works.