Why does `mutt` fail to send the mails with error `Couldn't lock /home/test/sent`?

Issue

• While sending mails using mutt, the mail was not sent and below message was displayed.

$ mutt -s "Test message" test@example.com < testfile.txt
fcntl: Function not implemented (errno = 38)
Couldn't lock /home/test/sent
Could not send the message.

• The file sent is available in home directory.
• The permission on the home directory is 755.
• It happens regardless of whether or not there is a maildir, Maildir, Mail, etc. directory in home directory as well.
• Sending mails using mail command is successful.