In order to configure the custom domain name on a Google Blogspot account, you will need to perform 3 steps.
Step 1: BlogSpot Change
you will have to log into your Blogger account and go to the Settings page.
In the Settings page, there is a section called "Customize your blog". Click on that.
Head to section "Publishing Section".
Do click on custom domain. Do put a domain and hit save.
First Error: Blogs may not be hosted at naked domains. so put www or any sub-domain. example www.abc.xyz or blog.abc.xyz.
Now this time you will save you will get Second Error. The Error say "we have not been able to verify your authority to this domain...". Copy the Entire Error into text editior. Here it asks you to update the CNAMEs. you will get 2 CNAMEs.
1. Name: www, Destination: ghs.google.com
2. Name: alphanumeric_id(unique), Destination: unique_url
Step2: Domain Provider Change
Now Go to your domain provider. I am using the NameCheap so I will login into it and open the dashboard.
For the domain you want to manage, click Manage.
Now Click on Advanced DNS. Here you will see option to add the CNAME record. Click "Add New Record".
After Adding 2 CNAMEs Record that we got from blogspot, it will look like this.
Click on Save all Changes and it's done. Wait for 15 to 30 min. Repeat the Step-1 again and this time it will be linked.
Step3: Enable HTTPS
By default, Blogger blogs are https enabled but when configure a custom domain we need to perform a extra few steps.
You need to add 4 A record in DNS setting(where we previously added the CNAME record). So total we will have 6 records(4 A records + 2 CNAME record) and set the value like below:
Do Note: If A-records for yourdomain already exist, you should remove existing A-records.
These IPs are provided by google:(link to post at bottom)
That's it. Check in sometime. your domain will point to now blogger. If still facing any, comment below and let us know.
PS : https://support.google.com/blogger/answer/1233387
Thanks