PKI-04015: Trusted cert cannot be removed

Trying to remove the trusted certificates from the wallet and getting the errors 

$ orapki wallet remove -wallet . -trusted_cert_all
Oracle PKI Tool : Version 11.2.0.4.0 - Production
Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved.

Enter wallet password:
PKI-04015: Trusted cert cannot be removed. CN=A,O=B,C=C

SOLUTION

$ orapki wallet display -wallet .
Oracle PKI Tool : Version 11.2.0.4.0 - Production
Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved.

Enter wallet password:
Requested Certificates:
User Certificates:
Subject:        CN=A,O=B,C=C
Trusted Certificates:
Subject:        CN=A,O=B,C=C
$orapki wallet remove -wallet . -trusted_cert -dn "CN=A,O=B,C=C"
$ orapki wallet remove -wallet . -cert_req -dn "CN=A,O=B,C=C"
$ orapki wallet display -wallet .
Oracle PKI Tool : Version 11.2.0.4.0 - Production
Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved.

Enter wallet password:
Requested Certificates:
User Certificates:
Trusted Certificates:

“ORA-28367: wallet does not exist” When Opening TDE Wallet

ORA-28367 error appears when opening the TDE wallet/keystore.

In 11c:

SQL>ALTER SYSTEM SET WALLET OPEN IDENTIFIED BY "software_wallet_password"; 
ALTER SYSTEM SET WALLET OPEN IDENTIFIED BY "software_wallet_password"
*
ERROR at line 1:
ORA-28367: wallet does not exist

in 12c:

SQL> ADMINISTER KEY MANAGEMENT SET KEYSTORE OPEN IDENTIFIED BY "software_keystore_password";
 ADMINISTER KEY MANAGEMENT SET KEYSTORE OPEN IDENTIFIED BY "software_keystore_password"
*
ERROR at line 1:
ORA-28367: wallet does not exist

CAUSE

1) Please check sqlnet.ora in place.

2) Check the format of “ENCRYPTION_WALLET_LOCATION” in sqlnet.ora right as the following:

ENCRYPTION_WALLET_LOCATION=
    (SOURCE=
      (METHOD=FILE)
      (METHOD_DATA=(DIRECTORY=/var/opt/oracle/dbaas_acfs/TESTDB/tde_wallet)))