Interface Endpoint fail to resolve DNS Name

Trying two accounts of my organization and I'm kinda lost. I provided the Service Endpoint in Account B, created a service name, and allowed the Account A to access it. Then in Account A I created the Interface Endpoint, selected "Other Endpoint Services" I entered the service name from Account B, and were able to verify the service name.

I already used the Reachability Analyzer, to check if the ENI from my ECS arrives in the ENI of my Interface Endpoint, and it works fine, they are in the same private VPC and the same SG. I'm probably missing some other stuff, it's my first time doing this...

Right now I have (Account A) ECS Task -> Interface Endpoint (Account A) -----> (Account B) Service Endpoint -> NLB -> AmazonMQ (Account B).

When I try to run my ECS Task I get an "Name does not resolve" error, I looked into the SDK I'm using and got that the issue is due to DNS not resolving.

On both VPCs DNS hostnames and resolution are enabled.

I got this print from a video, I'm not supposed to use those DNS names?

I tried to use the three I got and didn't work. And Private DNS name is disabled ATM. Oh and I'm trying to connect using Websockets, but since it's TCP I imagine this isn't an issue.