ORA-19815: WARNING: db_recovery_file_dest_size is 100.00% used,

SQL> startup
ORACLE instance started.

Total System Global Area  778387456 bytes
Fixed Size                  1374808 bytes
Variable Size             385877416 bytes
Database Buffers          385875968 bytes
Redo Buffers                5259264 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 4152
Session ID: 5 Serial number: 3

Check the alert log for further investination.
==============================================
contents from alert log
=======================
ORA-19815: WARNING: db_recovery_file_dest_size of 4039114752 bytes is 100.00% used, and has 0 remaining bytes available.
Errors in file c:\app\rpilla\diag\rdbms\mntest1\mntest1\trace\mntest1_arc2_4956.trc:
ORA-19809: limit exceeded for recovery files
ORA-19804: cannot reclaim 2866688 bytes disk space from 4039114752 limit

ORA-19815: WARNING: db_recovery_file_dest_size of 4039114752 bytes is 100.00% used, and has 0 remaining bytes available.
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You have following choices to free up space from recovery area:
1. Consider changing RMAN RETENTION POLICY. If you are using Data Guard,
   then consider changing RMAN ARCHIVELOG DELETION POLICY.
2. Back up files to tertiary device such as tape using RMAN
   BACKUP RECOVERY AREA command.
3. Add disk space and increase db_recovery_file_dest_size parameter to
   reflect the new space.
4. Delete unnecessary files using RMAN DELETE command. If an operating
   system command was used to delete files, then use RMAN CROSSCHECK and
   DELETE EXPIRED commands.
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I used the 4th suggestion by deleting archive log files from db_recovery_file_dest.

login

rman target /

list backup;
list copy;
delete archivelog all;