I was recently working with Access Services in SharePoint 2013 in my dev environment, and every time I created a new App for access I was immediately confronted with the following error “Sorry, something went wrong. An unexpected error has occurred.
Unexpected indeed! Thanks for that very informative error message, your politeness however is of little practical use to me. After spending more time than I care to admit publicly, we were able to eventually track this problem down to the fact that the account running the Access Services service application didn’t have the appropriate permissions to the SharePoint content database. I was using a domain account of CONTOSO\sp_accsvc to run the service application. To fix the problem, we ultimately needed to grant the CONTOSO\sp_accsvc account access to the “SPDataAccess” role in the SharePoint configuration database (in SQL Server). After doing that (and running an iisreset on the SharePoint box) POOF! I’m creating Access Apps error free!
Hopefully this will save someone some time (like myself in the future once I forget).