Receiving Method not found 405 error for a POST request

I am testing an API using the POST method, it shows the status as “405 Method Not Allowed”. But, when I change the method to Get, it works fine (status becomes 200 ok).
I have verified the documentation of the API and it is POST method only.
I have used this API previously in other system and it used to work fine without any issues. I have done postman setup recently in my new system and facing this issue. (specifically to one POST request)

Screenshot of error:

the URL is in the format as below,
https://:/xxxx/yyyy?param1=&param2=

Appreciate if someone can help me in resolving this error.

Thank You