Hi Johan,
Please try to check the following steps - the authorization issue may be that the underlying table does not exist or you do not have select permissions on the table that you want to expose.
You can do, what I just tried few minutes ago, create a new application project based on the empty HANA XS template where you have just the .xsaccess and .xsapp files. And then create the xsodata file, as I have it below:
test.xsodata file:
service
{
"SCHEMA_NAME"."TABLENAME" key generate local "GEN_ID";
}
And just check that your user has DB permissions on the SCHEMA_NAME - in my case I used the schema with the same name as my user, hence I have full access.
And check if you can access the XSODATA service then.
Fingers crossed,
Pavel