How to delete all the root mail in linux by mutt + root mailbox full or 5.2.2: Permanent Failure: Mailbox Status: Mailbox full

How to delete all the root mail in linux by mutt

#mutt
/root/Mail does not exist. Create it? ([yes]/no):
yes

Then press "D"
At the bottom it asks "Delete messages matching:"
 ~s .*

-*-Mutt: /var/spool/mail/root [Msgs:46339 New:46339 Del:46339 48M]---(date/date)-

press "q" to quit and "y" to confirm