How to connect to postgres read replica in Hasura

Question

I have the main postgres database running with Hasura. I want to add a new Hasura service that connects only to the read replica.

But it is getting this error

..."hint":"You can use REPEATABLE READ instead.","message":"cannot use serializable mode in a hot standby","status_code":"0A000"...

I also tried adding --tx-iso=repeatable-read but no luck.