WebAPI error - 9004010A, An unexpected error occurred while processing the request

[Sahil]

Hi Folks,

I am trying create a record of custom entity using Power Portal Web API. The custom entity has a lookup of contact entity that has to be populated. API works fine if the lookup is not included. Below error is shown when I try to set the lookup:

I have checked site settings and table permissions, these look fine. The logged in user has create/read/write/append permissions on the custom entity along with read/append permissions on the contact entity.

Please help, thanks in advance.

[Sahil · Accepted solution]

The error has been resolved, found my mistake. I was setting the lookup value incorrectly. It was 

"contacts/(id)" instead of "/contacts(id)"