Hello & Welcome to JustAnswer.
What is the part after the @ symbol of your e-mail address?
You have two options.
Either increase the size of the mailbox; if you access to the mail control panel.
OR delete email messages by logging into your webmail.
where do I find mail control panel
How are you currently accessing mails?
hmm - the mail control panel is a web address; it is only known by the administrator of the hosting who setup the e-mail.
Another option is to add e-mail account as imap, and then delete the messages (older ones)
I can remotely connect to your system to do this
Would you like me to do that?
no we have to retain mail for reference thank you for your help
In that case - i would suggest that you speak to the administrator who setup the e-mail and tell them to increase your space.
OR if you go the method i suggested, you can save e-mails on your PC and delete them from the mailbox.
Will contact mail administrator
No problem - thanks