BigQuery API did not answer query in time

I'm playing around with Windmill Cloud (trial). I've created a BigQuery resource and a SQL script that uses that resource:

-- @schema (string)
-- @table (string)

EXECUTE IMMEDIATE FORMAT("SELECT * FROM %s.%s LIMIT 100", @schema, @table)

-- @schema (string)
-- @table (string)

EXECUTE IMMEDIATE FORMAT("SELECT * FROM %s.%s LIMIT 100", @schema, @table)

When I test the script with certain tables I get "BigQuery API did not answer query in time". Any idea what is going on here?