RMAN-08138: warning: archived log not deleted - must create more backups

 delete archivelog until time 'sysdate - 7';

archived log file name=+RECO01/xxxxxxxxxx/ARCHIVELOG/2023_08_16/thread_1_seq_1758.12751.1145022793 thread=1 sequence=1758
RMAN-08138: warning: archived log not deleted - must create more backups
archived log file name=+RECO01/xxxxxxxxxx/ARCHIVELOG/2023_08_16/thread_1_seq_1759.13482.1145040079 thread=1 sequence=1759
RMAN-08138: warning: archived log not deleted - must create more backups
archived log file name=+RECO01/xxxxxxxxxx/ARCHIVELOG/2023_08_16/thread_1_seq_1760.10421.1145057009 thread=1 sequence=1760


check 
CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO DISK;



use force

delete noprompt force archivelog until time 'sysdate - 7';