I am trying to clear away unwanted emails; I have too many in my mailbox, they are not responding to the delete tab.

Is your email account type POP3 or IMAP ?

If it is a POP3 account, this problem (used space) may not go away. I have the same problem with my iPhone 7 and had it with my iPhone 5.

Try deleting your POP3 email account, and then create an IMAP email account.

Hi Susan,

I have taken the sentence below from an Apple Help page.
I hope this finds you well,
Niall

Go into Settings > Mail, Contacts & Calendars, select the account you don't want, and then choose to delete it.

Look for the Accounts section below your mailboxes (see image)

Select the account that you want to delete emails from. Select the folder (for example -Trash) Tap on this folder, and you will see the word "Edit" at the top right. Tap on Edit, select the emails that you want to delete (a blue check mark will appear to the left of each selection), and then look for the word "Delete" at the bottom right of the list of emails that you have selected. Tap on Delete and that should solve your problem.

It appears that someone has hacked in to your account, which is why so many of your emails were deleted. I would recommend changing your password in order to make this issue go away.

You are getting a message saying "mailbox is full" when you receive a message, right? What kind of message is that? Is it a text or an email message?

If that's an email message, you may need to delete all of the sent items and see if you will get the same problem. If it's a text message, delete the copy of sent text messages.

Usually, sent items does not look like it's eating up your storage, but the truth is, it's causing your mailbox to get full.

Thank you and good luck!

see here is the solution.. go to messaging->options->email->mailboxes->select ur emailmailbox->options->delete mailbox
THen configure your mailbox again

You should be able to see those emails after hitting F5 from the keyboard a couple of times.

Also, try clearing your cache:

For IE, click Tools, Internet Options. In the general tab, under Delete browsing history, delete ALL.

Further, flush your DNS. Open a command prompt, then type:

ipconfig /flushdns

Hi,
 
Generally users of POP3 email like to download messages to their PC and take them off the central server. But sometimes you'll want to leave them there so you can access them again. Like most other mail client applications, Outlook Express can be configured to leave messages on the server indefinitely or for a specified period of time.
 
How to Set Outlook Express To Leave Email Messages On The Server
Open Outlook Express
Select Tools/Accounts.
Click on the Mail tab, highlight YourAccount and click on the Properties button.
Click on the Advanced tab.
In the Delivery section, select the checkbox to Leave of copy of messages on server.
Select the appropriate checkbox to delete the messages from the server after a certain number of days or until the messages are deleted from the Deleted Items in Outlook Express. (Do also check you mailbox size from your internet provider, If you get a lot of emails you may fillup your mailbox fast)
 
For Outlook 2003
go to Tools > Options.
Select the Mail Setup tab from the Options dialog, and click E-mail Accounts.
Select the email account and click Next
Under the Delivery section of the Advanced tab, Checking the Leave a copy of messages on the server checkbox instructs Outlook 2003 to leave a copy of your emails on the server indefinitely
 
You will find the same options on all email software. Once you have Set this on all the computers, you will get the same mails on each one.
 
Hope this helps. Please rate your feedback!
Thanks,
VJ

hi i think you have a lot of spam mails in your mail box or bulk.

try emptying the entire box to see if it would respond.
yahoo mail services have small capacity for the individual user


if this does not work then consider deleting it from the server

Hi

Pls check if if you have enough free space in the mail box as the sent mails will also be counted towards the size.
Pls delete unwanted mails and also sent mails.
Pls check with the mail server settings i.e. incoming mail server and outgoing mail server information.