It seems I can send messages only in case the scope ALL is assigned. If I limit the permissions of the bot to READ_CONVERSATIONS only it is failing with:
{"name":"app","hostname":"ldap-01-fth01ti-de","pid":1740,"level":50,"msg":"[APP]: { [Error: Internal error with Client Credentials Grant authentication]\n code: 'SDK_ERROR',\n message: 'Internal error with Client Credentials Grant authentication',\n stack: 'Error\n at Error (native)\n at Error.circuit.Error (/home/ldapuser/bin/node_modules/circuit-sdk/circuit.js:309:22)\n at /home/ldapuser/bin/node_modules/circuit-sdk/circuit.js:46269:32\n at process._tickCallback (node.js:438:9)' }","time":"2018-07-24T08:14:27.930Z","v":0}
Are these scopes supposed to be used to limit the bots capabilities in case Grant Type CLIENT_CREDENTIALS is used?