Check the Storage Space
https://one.google.com/storage
It Will something Look Like This:
If you've confirmed that Gmail is eating up a significant amount of storage, keep on reading.
Delete junk mail
-By default, Gmail attempts to sort emails from retailers, mailing lists, and other automated lists into the 'Promotions' tab.
-If you want to include messages that Gmail thinks are promotional emails, add "OR category:promotions" (without quotes) to your search, like in the below screenshot.
If you're on the desktop Gmail web app (as opposed to the mobile app), you can click the checkbox in the top bar to select all messages at once, then move them all to the trash. After you click the checkbox, you can optionally click the 'Select all conversations that match this search' and then the trash button to delete every single matching message.
After you're done wiping them out, open the Trash folder in the Gmail sidebar (you might have to click 'More' in the sidebar first), and click 'Empty trash now.'
Now check your storage dashboard again and see how much space was recovered. If you still need more room in your account, there are a few more ways to clean up storage.
Delete large attachments
Emails with large attachments, either sent or received by you, can also be taking up a significant amount of space.
Do a search for "size:5m" (without the quotes). This will display all emails that are 5MB or larger in size.
Here you can look at each individual message, and delete the ones you don't need to keep around.
Again, make sure to clear your Trash once you're done.
Delete old emails
Gmail also makes it easy to delete all messages sent before a given date using the "older_than" search operator.
For example, if you search for "older_than:1y" (without the quotes), you'll see all your emails older than 1 year old.
You can change the number of years by editing the number before the "y." Gmail also supports searching by months or days by using "m" or "d" instead, respectively.
*Blue Colour Underlined Lines are the Links
Special Thanks to @Interchuppi For Highlighting the issue.
-Thank You For Your Support.
Source: Experience of Same Issue occurred in the Past And Of course the Internet .
