[Sync] I can't add my Gmail Account in Add External Mail.

Please refer to the steps below and try again.

1. Check if Gmail POP is enabled.

►Go to check if Gmail POP is enabled.

2. Use App Password: Log in with App Password if you use 2-step verification. 

 (You can no longer register external mail by only using your username and password since Google login policy will be changed from 2022/05/30.)

► Go to Google Notice

► Set 2-Step Verification for Google Account 

► Create App Password in Google Account

3. If none of the tips above solves your problem, please visit the "Allow Access to My Google Account" page and follow the instructions.

 For more details, please refer to Google Help.