I am receiving below error while trying to edit the permissions of the objects in my bucket
Cannot get legacy ACL for an object when uniform bucket-level access is enabled.
It seems like you have selected access control as uniform, you can change it to fine-grained, if you want to add permissions in object level.
To do this you can click on the 3 buttons present on the right of your bucket - click on edit bucket permissions - select switch to fine-grained under access control - select fine grained - click save.