Solved - java.sql.SQLException: ORA-00257: Archiver error. Connect AS SYSDBA only until resolved.

 The issue occurs when the archivlogs or backups ocupy too much space. You can follow the steps below to remove some of the files.

1. Login to your system as the oracle user.

2. Type rman on the command line and hit the enter.

     [oracle@linux]$> rman

3. Connect to the target database.

     RMAN> connect target

4. Delete the backups or obsolete backups.

      RMAN> delete obsolete;

      or delete all backups:

      RMAN> delete backup;

5. Remove archive logs.

      RMAN> delete force copy of archivelog all;

6. RMAN> exit