My OWA mailbox is full.
I can't send or receive either. 
How can i do for this problem??? and 
I use MS outlook application also. 

Before this error, i send/receive all email from OWA by MS outlook application.
When i done this, mailbox size is fine again. I think email is moved to MS outlook application.
Now it's not fine. It's just copy to MS Outlook.
When I delete email from OWA, it's also delete in MS outlook.
I'm just beginner of Exchange Server. 
Please suggest how to solve this problem?
I'm using Exchange Server 2010.

#shinminsymon 

Are you looking at the same mailbox in Outlook and OWA? Because if so, you'll see exactly same content in both.

Check your mailbox database quotas:

Get-MailboxDatabase -Identity "Your Mailbox Database Name" | fl *quota*

There are few quotas:

ProhibitSendReceiveQuota - this is probably the one you've exceeded
ProhibitSendQuota
RecoverableItemsQuota
RecoverableItemsWarningQuota
CalendarLoggingQuota
QuotaNotificationSchedule
IssueWarningQuota

If your mailbox is set up to have default quotas from mailbox database then you need to adjust those:

Get-MailboxDatabase -Identity "Your Mailbox Database Name" | Set-MailboxDatabase -ProhibitSendReceiveQuota "your limit like 2GB" -ProhibitSendQuota "limit" -IssueWarningQuota "limit"

Note this is for Exchange 2013 but this settings will be the same for 2010.

I think your outlook client may have have auto archive feature enabled hence when you log in to outlook client it moves all mail to pst and mails box is below limit. 

When you delete mail from owa you are also deleting the server copy hence it ends up deleting mails from your outlook clinet.

I would suggest you to either increase the mailbox qouta from exchange server or delete unwanted mails from OWA if you do not have access to outlook client right now.

If you have access to outlook client sort mails by size and move them to pst to solve this quickly.

Hi, Thank for your suggestion.
I just enabled auto archive feature from

Tools > Option > Other tab > Auto Archive > Run Auto Archive every 16 Day

Is that true brother?
And now i can only access outlook client. 
I don't understand how to move larger size mail to pst.
Just Send/Receive all button click? 

Yes thats correct and just make sure that you click on "Apply this settings to all folders now"

moving mails to pst by size i meant was in outlook just sort the mails with size then which ever mails size is bigger for e.g 5 mb or more just select and move it to the pst which is mapped in your outlook if there is no mapped pst just create a new pst and move it.

Yes brother, i understand now. 
and also Ok my problem. 
Thank you so much.