I am using Events-Planner plugin on my site to register kids for a camp. It has worked great so far. Recently I am having people get an error message when going through the registration process. I have Events Planner using PayPal Express Checkout. I can't reproduce the error but others have been telling me they get an error after they go through the process of selecting their camp and inputting their info. The click the confirm and then they get this error:
ERROR: Authentication/Authorization Failed. You do not have permissions to make this API call
I went back through the verified the API settings and all those are correct. I went through the process myself and all worked no problem.
What could be the cause of this and what can I do to fix it? Why would some people get this issue and others have no problems?
Page I am working with is http://granbyschool.com/online-registration/.
Any help would be greatly appreciated. Thanks.