Ansys Error: Unassigned interface zone detected
 

Hi everyone,
I have a very simple 2D mesh for a rectangular cylinder with a rectangular computation domain. On Checking the Mesh in Ansys (Solver: Fluent) I get the following Warning and Error.

WARNING: Unassigned interface zone detected for interface 2
WARNING: Unassigned interface zone detected for interface 6
WARNING: Unassigned interface zone detected for interface 7
WARNING: Unassigned interface zone detected for interface 8
WARNING: Unassigned interface zone detected for interface 9
WARNING: Unassigned interface zone detected for interface 10
Checking junction nodes.
Error: interface zone 2 has two adjacent cell zones.

I have seen similar threads in earlier posts and I think I understand what it means but I can't find where is the problematic part in my mesh.

Details of my Project:
1. The solver is set to Fluent.
2. The interface was defined inside the workbench in Design Modeller.
3. Haven't used any word like zone, surface, interface for named-selection or defining surface, etc.

I am just totally stuck. I will attach an image if it helps.

What I would like to understand:
1. How to detect where the unassigned interface zone is?
2. Does the error have something to do with the Warnings?
3. How to solve the Warning and Error?

Please let me know if I need to upload anything else. Thanks.