I'm using Node.js Zoho SDK and getting "Error: Missing configuration for Zoho OAuth service: refresh_token" during execution of some get and search APIs.

I've implemented the saveOAuthTokens(token_obj), updateOAuthTokens(token_obj) and getOAuthTokens() methods. 

I call ZCRMRestClient.initializeWithValues() method before test execution with values of  client_id, client_secret, init_refresh_token and mysql_module. 

I payed attention, that once expiry time is reached and mysql_util.updateOAuthTokens function is called, the object doesn't have a refreshtoken attribute. 

That leads to above error.

What do I miss?