I am not able to start an instance of Oracle Database - ORA-00205: error in identifying control file, check alert log for more info

When I want start the server instance I get the following message:

SQL> startup
ORA-32004: obsolete or deprecated parameter(s) specified for RDBMS instance
ORACLE instance started.

Total System Global Area 2.1475E+10 bytes
Fixed Size                  7654304 bytes
Variable Size            7381976160 bytes
Database Buffers         1.4026E+10 bytes
Redo Buffers               59453440 bytes
ORA-00205: error in identifying control file, check alert log for more info

When I check the log, this is what I obtain:

<msg time='2020-07-24T12:29:30.623-05:00' org_id='oracle' comp_id='rdbms'
 type='UNKNOWN' level='16' host_id='li2qbdeocf01'
 host_addr='10.96.143.87' pid='29605'>
 <txt>ORA-00210: cannot open the specified control file
ORA-00202: control file: &apos;+DG_REDO_02/EOC9DB/CONTROLFILE/current.262.912594295&apos;
ORA-17503: ksfdopn:2 Failed to open file +DG_REDO_02/EOC9DB/CONTROLFILE/current.262.912594295
ORA-15001: diskgroup &quot;DG_REDO_02&quot; does not exist or is not mounted
ORA-27140: attach to post/wait facility failed
ORA-27300: OS system dependent operation:invalid_egid failed with status: 1
ORA-27301: OS failure message: Operation not permitted
ORA-27302: failure occurred at: skgpwinit6
ORA-27303: additional information: startup egid = 1000 (oinstall), current egid = 0 (root)
ORA-00210: cannot open the specified control file
ORA-00202: control file: &apos;+DG_REDO_01/EOC9DB/CONTROLFILE/current.262.912594295&apos;
ORA-17503: ksfdopn:2 Failed to open file +DG_REDO_01/EOC9DB/CONTROLFILE/current.262.912594295
ORA-15001: diskgroup &quot;DG_REDO_01&quot; does not exist or is not mounted
ORA-27140: attach to post/wait facility failed
ORA-27300: OS system dependent operation:invalid_egid failed with status: 1
ORA-27301: OS failure message: Operation not permitted
ORA-27302: failure occurred at: skgpwinit6
ORA-27303: additional information: startup egid = 1000 (oinstall), current egid = 0 (root)
 </txt>
</msg>

It asks for a control file, but the variable +DG_REDO_02 is strange for me. I don’t know what it refers to. This server was working well, until an unexpected restart of the OS happened.