“Only reserved document ids may start with undersc

Question

I'm working with CouchDB and am trying to search a db using _find. I am currently running into the following error:

error: 'illegal_docid',
  reason: 'Only reserved document ids may start with underscore.',
  scope: 'couch',
  statusCode: 400,
  request:
   { method: 'POST',
     headers:
      { 'content-type': 'application/json',
        accept: 'application/json',
        Host: 'example.com',
        Referer: 'https://example.com' },
     uri: 'http://XXXXXX:XXXXXX@206.189.178.130:5984/gc_common/_find',
     body: '{"selector":{"_id":"taglist"}}' },
  headers:
   { date: 'Thu, 25 Jul 2019 22:04:09 GMT',
     'content-type': 'application/json',
     connection: 'close',
     'cache-control': 'must-revalidate',
     statusCode: 400,
     uri: 'http://XXXXXX:XXXXXX@206.189.178.130:5984/gc_common/_find' },
  errid: 'non_200',
  description: 'couch returned 400' }