Constraint in ON CONFLICT clause has no associated index

I have this simple setup

    CREATE TABLE stop (       id INT UNIQUE,       name TEXT,       PRIMARY KEY(id)     );      CREATE TABLE line (       id INT UNIQUE,       name TEXT,       PRIMARY KEY(id)     );      CREATE TABLE line_stops_sequence(       id SERIAL PRIMARY KEY,       line INT,       stop INT,       CONSTRAINT fk_line FOREIGN KEY(line) REFERENCES line(id),       CONSTRAINT fk_stop FOREIGN KEY(stop) REFERENCES stop(id)     ); 

When I launch the following sentence

INSERT INTO line(id, name) VALUES (1, 'Line 1'); INSERT INTO stop(id, name) VALUES (2, 'Stop 2'); INSERT INTO line_stops_sequence(line, stop) VALUES (1,1), (1,2) ON CONFLICT ON CONSTRAINT fk_stop DO NOTHING; 

I get constraint in ON CONFLICT clause has no associated index;

I know I’m inserting an stop id that is not included in the stop table. The idea is that I want to ignore the INSERTs that have conflicts. In the example it is just two items, but I’m inserting bulk data.

How can I do it without having to manually check the result of the query? Is there anyway to do it with the SQL sentence?