Welcome back Ayuthan,
Just to confirm, were you able to check to see if those were included in Settings > Notifications > Scheduled Summary? We want to be sure it didn't get inadvertently added.
Additionally, are you receiving any notifications such as a badge app icon? If you go to Settings > Notifications > Mail > Customize Notifications > Tap Account, do you see Badges and Alerts enabled? If not, let's go ahead and enable both and test to see if the same behavior occurs. This can help us determine if a different setting may be affecting Mail.
Lastly, let's go to Settings > Mail > Fetch New Data, after tapping on Fetch New Data, what do you see showing for the account listed there? Push, Fetch, or Manual? At the bottom, is Fetch set to Automatically?
We look forward to hearing back from you.
Have a lovely day!