PostgreSQL: canceling statement due to conflict with recovery

I fetch this error in my code , and my database is on AWS RDS instance.

OperationalError: canceling statement due to conflict with recovery DETAIL: User was holding shared buffer pin for too long.

and i found solution to change value of

max_standby_archive_delay = -1
max_standby_streaming_delay = -1  

But AWS is not allow me to change those values . is there any other way to solve this error.