I'm pretty sure this is by design. I believe you'll need to point to the specific resource in order to make the connection as Tableau won't recognize a general area. You may want to consider contacting support to see if they can verify the time.
I had exactly the same. I work with Odata v2. my odata url worked with excel import and in the browser. but Tableau requires a specific url that is compliant to the URI convention. Our dev team looked into it and we had to change the URL (according to this URI Conventions (OData Version 2.0) · OData - the Best Way to REST ) in order for it to work with TAbleau.
apparently we used a (working !!) Odata link that fed JSON language but tableau cannot read that so we had to modify the URL.
Old link that worked in browser but not in Tableau: https://app.<our domain>.com/odata/persons
New url that does work in tableau:https://app.<our domain>.com/odata/persons?$format=atom
So I would advise you to find a developer who can look into it for you.
Once it works I am afraid you'll experience a whole different type of problems, because working with Odata sources is much different from working in tableau with Odata-Excel dumps ... That's where I am now...