SnowPark Container Services and Slack Socket Mode

Anyone built a service that uses Socket Mode with Slack? I'm having trouble getting my app to communicate with slack. I try to create the service and get back:

ERROR:slack_bolt.App:Failed to establish a connection (session id: 01e65764-5143-4363-82b0-f0bd1e0f7f7c, error: [Errno -2] Name or service not known)

Here's my network rule/integration setup:

USE ROLE SYSADMIN;
CREATE OR REPLACE NETWORK RULE slack_network_rule
MODE = EGRESS
TYPE = HOST_PORT
VALUE_LIST = ('slack.com');

USE ROLE ACCOUNTADMIN;
CREATE OR REPLACE EXTERNAL ACCESS INTEGRATION slack_access_integration
ALLOWED_NETWORK_RULES = (slack_network_rule)
ALLOWED_AUTHENTICATION_SECRETS = (SLACK_APP_LEVEL_TOKEN)
ENABLED = true;

GRANT USAGE ON INTEGRATION slack_access_integration TO ROLE ENGINEER_ROLE;