Well, you cannot block message from a certain domain or address but you can send those unwanted messages to trash by setting up filters which can never be seen by you.
There are some steps that help you to Block Email Senders with the use of Gmail Filters:
1. First, open the message you want to block.
2. Go to the more option in the mail in the right corner of the screen.
3. Now click on the ‘Block Sender’ option. Like in the given example, ‘Block Ola Cabs’.
4. Then a pop-up will appear. It will ask for your confirmation in blocking the respective mail.
5. Click on ‘Block’ and that respective user will be blocked.
A confirmation message is shown on the top of the mail just like in the below mentioned picture:
There are some steps that help you to Unblock Email Senders with the use of Gmail Filters:
1. Log into your Gmail account and click on the ‘Settings gear’ icon which is in the right most corner of the screen.
2. Click on the ‘Settings’ option.
3. Now select ‘Filters and Blocked Addresses’. This displays all the blocked email addresses.
4. Click on the checkbox provided before the sender you want to unblock. Like in the given example, OlaCabs<firstname.lastname@example.org> is selected.
5. Then click on ‘Unblock selected addresses’ as shown above. Pop up screen appears on the screen. It will ask for your confirmation on unblocking the respective sender.
6. Click on ‘Unblock’. Now Gmail would show a confirmation message on the screen that the respective email sender is unblocked.