Postgres db help

By looking to the error, it seems usage grant on schema UCM is missing for the user trying to insert data into the table.

Could you try to give usage grant "grant usage on schema ucm to <user>;"

I have addressed your concerns as follows-

Please allow me to mention that this error arises when you do not provide the access to the schema you are trying to make modification/ selection from.

I would recommend you try to login from your master user and grant the particular user access on the schema 'ucm'.

Syntax to do the same:

"grant usage on schema ucm to <user>;

You can also kindly refer to document attached below for user and role grants in RDS Postgres [+]https://aws.amazon.com/blogs/database/managing-postgresql-users-and-roles/

I sincerely hope this helps!