Enable Gmail Access for Non-Google Applications

The steps below will show you how to change Google settings to allow access for non-Google applications. Allowing access to a Gmail account by a less secure application is one example.

Change Google Account Setting

1. Log in to Google Account settings. https://myaccount.google.com

2. In the left navigation panel, find and click on Security.

3. On the security page find the "Less secure app access" section towards the bottom of the page. Click on the "Turn on access" link.

4. Select the Allow less secure apps button.

References
1. https://support.google.com/accounts/answer/6010255?p=lsa_blocked&hl=en&visit_id=636910285396496639-1159857850&rd=1