Hi
You likely see this as you don't have active NetApp contract assigned to your user. you will need to provide NetApp via the feedback form a serialnumber of an in-contract device to be able to access downloads.
Please note that NetApp take down documents and downloads for products after the 3 years period of Self-Service Support (Where it's no longer supported by NetApp) for the ONTAP 7.3 version compatible with FAS2020 that's just past a month ago, and they can technically take it down at any moment now (currently it's available)
https://mysupport.netapp.com/info/web/ECMP1147223.html#ontap_svst
Gidi