Revindex Storefront: 19.14.1.0

When I try to make a request to GetProductAttributeDefinitionSelection endpoint i'm getting:

<?xml version="1.0" encoding="utf-8"?>
<response>
  <code>4004</code>
  <message>Service not found.</message>
  <return />
</response>

When I try to make a request to GetProductAttributeDefinitionSelections endpoint i'm getting: 
<?xml version="1.0" encoding="utf-8"?>
<response>
  <code>4003</code>
  <message>Service execution error. Object reference not set to an instance of an object.</message>
  <return />
</response>