How to install on an external drive's APFS partition?

[steffi]

Currently when trying to use the earlier downloaded Install macOS Catalina.app to install on an external drive I end up getting a "Unable to verify macOS" error with 2 minutes left.

 

[FilmIndustryGuy]

is it a T2 chip Mac cause I was also getting issues until I turned off FileVault and then turned off security in T2 settings. Then everything worked.

 

[steffi]

Yes it has a T2 chip

and I’ve gone from full to medium security to see if that works.

update it’s installing now after reboot so it’s further at medium now