How to specify secure strings (MACS) in pgadmin3 astra linux?

Question

linux

I'm trying to create foreign keys in a table, but I'm getting an error,

what are these protected rows?
in the table settings I set row safety, but still an error,

but where MACS is set - I don’t see
, maybe I need to fill in the tables first?

and in general why without it it is impossible to create a foreign key?