You need to go your google account to set 2nd Authentication scroll down Create App Password.

1. Go to your Google Account and choose Security on the left panel.

2. On the Signing in to Google tab, select App Passwords.

If you don’t see this option, it might mean that:

Two-step verification is not set up for your Google account.

Two-step verification is set up for security keys only.

Your account is used through work, school, or another organization.

You’ve turned on Advanced Protection for your account.

3. Click on Select app and pick the app you’re using.

4. Click Select device and choose the device you’re using.

5. Click on Generate.

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1 - Contact customer service of your hosting server to set firewall allow gmail smtp port 587

2 - follow the steps on this webpage to install the latest version phpmailer to your hosting