Specification does not match any archived log in the repository

In my case, after enabling the archivelog mode i forgot to open the database. So during the full backup i got a message saying below and it cancelled the backup.

Before:

specification does not match any archived log in the repository
backup cancelled because there are no files to backup

RMAN Backup did not complete as expected check file

FIX : Please check whether your database is in open mode or not, it should be open.

After :

channel ch11: backup set complete, elapsed time: 00:00:01
Finished backup at 27-FEB-17

released channel: ch11

Recovery Manager complete.
+++++++++++++++++++++++++++++++++++++++++
RMAN Command successful completion..
+++++++++++++++++++++++++++++++++++++++++
RMAN Backup did not complete as expected check file