If you have been trying to do updates via the Lifecycle Controller via FTP and they are failing. The FTP method can only obtain the catalog of updates, but not the update itself.
If you have a 14th Gen server with iDRAC9, you will need firmware release 126.96.36.199 or later to support HTTPS downloads properly
If you have a 13th Gen server with iDRAC8, you will need firmware release 188.8.131.52 or later to support HTTPS downloads properly
If you have a 12th Gen server with iDRAC7, you will need firmware release 184.108.40.206 or later to support HTTPS downloads properly
If you have a older server with iDRAC6 or older you will need to obtain updates from https://support.dell.com and install them based on your Operating System version.
Choose Firmware Updates, in Step 1 choose Network Share (CIFS or NFS or HTTP or HTTPS Server)
Step 2 choose HTTPS and Share Name/Address of downloads.dell.com
Step 3 wait for the Catalog to download and list the available updates for your hardware.