I'm having troubles with an odoo server error. We use our own installation of odoo 11 community edition and we installed custom modules. One of them is a rental module from webkul. It has an option to look at rental contracts but with all users except the initial admin account we get the error:

Odoo Server Error - Access Error
The requested operation cannot be completed due to security restrictions. Please contact your system administrator.

(Document type: Sales Order Line, Operation: read) - (Records: [13, 12, 9, 10], User: 64)

All users have the right to read/change all Documents. Even after duplication of the admin account that doesn't get the error, the duplicated accounts gets it. I checked settings->security->Record Rules but I can not see anything wrong there. Any ideas on what else I could try out to resolve this issue?