When you buy a new domain to use, you have to redirect your blogger domain, i.e .blogspot.com to the new domain name.
After redirecting it, your website will be working with www.yourdomain.com, but may not work without www.
This happened to me once, and to rectify the problem, log in to your blogger dashboard, go to settings, then you will see blog address.

Click edit, then click on the checkbox that says 'redirect yourdomain.com to www.yourdomain.com

Click on save
And that's all
After redirecting it, your website will be working with www.yourdomain.com, but may not work without www.

Click edit, then click on the checkbox that says 'redirect yourdomain.com to www.yourdomain.com

Click on save
And that's all

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