SharePoint 2016 Custom Web Part Issue

Question

I have developed several custom web parts for a new SharePoint instance. When I leave the web parts as a Sandbox Solution and deploy them to the server they display and function as intended for users in the Owners group.

For all other users, the web parts throw an Access is denied error. If I switch the web parts to a Farm Solution and deploy them to the site all of my non-Owners group users cannot get to the SharePoint site. They receive the

"Sorry, you don't have access to this page" message.

I have checked the permissions on all of the associated lists that these web parts pull data from and they are correct. Can anyone give me any insight as to why I am encountering these permission issues on my custom web parts?

Answer 1

I was able to figure out a work around.

All of the lists that my web parts were pulling data from resided on the top level parent site. I created a new sub-site and moved my lists to that site and it allowed me to deploy my web parts as non-sandboxed solutions without causing the permissions issue.

Still not sure why the issue was occurring though.

Answer 2

If you have use any resource files for the custom webpart try to keep those in source code folder and give the permissions to access that source code folder too, That solves the issue for me some times. you can hide the folder using the SharePoint Designer.