Elasticache Serverless Memcached "Connection closed by foreign host"

I am trying to set up a serverless Memcached for an ECS service deployed through Fargate, which is running a Golang app.

The service in ECS as well as the serverless Memcached are in the same VPC and have the same security group, where I allowed 11211 port access.

The Golang app throws a timeout when trying to connect to the Memcached.

I also set up an EC2 on the same VPC and security group from where I tried to connect with

telnet memcached-*.serverless.use1.cache.amazonaws.com 11211

Connected to default. memcached-*.serverless.use1.cache.amazonaws.com.
Escape character is '^]'.
stats
Connection closed by foreign host.

As soon as I run stats the connection is closed, as highlighted above.

PS: I tried setting up a cluster also. This one works as expected.