I have installed ARAS 12 out of the box and want to make use of REST API but could not find it, as when i try to call the odata it is not available at the location mentioned in the documentation, i.e. ../Server/odata,
Could spend some time on this and found useful link below.
Follow this link and retrieve bearer token. If you use this bearer token things are working fine for me.
Here are snapshots from Postman
Let me know if this helps