Cannot change postgresql 9.6 max_connections Ubuntu 16

Question

I'm running postgresql 9.6 with postgis on Ubuntu 16.04, and I'm running into a bizarre problem while running the tilemill app which is giving "too many clients already" error. So I go inside /etc/postgresql/9.6/main/postgresql.conf and I set

max_connections = 200;

and perform a restart without error.

sudo pg_ctlcluster 9.6 main restart

I check psql and run the following:

Meanwhile, if I were to go back inside /etc/postgresql/9.6/main/postgresql.conf and increase the following to a number greater than max_connections (5),

I cannot restart the server because:

ip-172-31-48-27 postgresq;@9.6-main[16228]: postgres: superuser_reserved_connections must be less than max connections

error image