I am running a cron job which executes the python script for reading gmail (2 min interval). I have used imaplib for reading the new mails. This was working fine until yesterday. Suddenly its throwing below error

imaplib.error: [AUTHENTICATIONFAILED] Invalid credentials (Failure)

and sometimes i am getting the below error

raise self.abort(bye[-1]) imaplib.abort: [UNAVAILABLE] Temporary System Error 

When i run the same script on a different machine. Its working fine. I am assuming that the host has been blacklisted or something like that. 
What are my options ? 
I cant generate the Credentials (Gmail API) as this is under company domain account.
Some apps and devices use less secure sign-in technology. So we need to enable Less secure app access option from gmail account.
Steps:

Login into Gmail
Go to Google Account
Navigate to Security section
Turn on access for Less secure app access

By following above steps, issue will be resolved.
reading gmail is failing with IMAP