ILM Policy - Help!>!>!>

Try;

PUT /filebeat-7.7.1-2020.09.22/_alias/filebeat-7.7

Then change;

With;

"rollover_alias": "filebeat-7.7.1"

You don't want to use filebeat-7.7.1-0000N as the alias, because ILM adds the -0000N part automatically when it rolls over.