ORA-19550: cannot use backup/restore functions while using dispatcher

Hello,

Apperciate your support in this issue

i want to delete all log files in RAC environment using rman but i found this error (attchated screenshot)

And this is my TNS entery:

NCPSLU=

  (DESCRIPTION=

    (ADDRESS_LIST=

      (ADDRESS=

        (PROTOCOL=TCP)(HOST=192.168.254.70)(PORT=1522)      

        (PROTOCOL=TCP)(HOST=192.168.254.71)(PORT=1522)

      )

    )

    (CONNECT_DATA=

      (SERVICE_NAME=ncpsluXDB)

    )

  )

after troubleshooting i found that it needs to add in the tns entery SERVER=DEDICATED but i found this tns error

<span class="pln" style="color: #303336;">TNS</span><span class="pun" style="color: #303336;">:</span><span class="pln" style="color: #303336;">could </span><span class="kwd" style="color: #101094;">not</span><span class="pln" style="color: #303336;"> resolve the </span><span class="kwd" style="color: #101094;">connect</span><span class="pln" style="color: #303336;"> identifier specified</span>