When I evaluate this:

@startuml
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response

Alice -> Bob: Another authentication Request
Alice <-- Bob: another authentication Response
@enduml


I get an error message:

Terminal 0 is locked, cannot read from it 

What is causing this?

Regards
Johann



--
Because experiencing your loyal love is better than life itself,
my lips will praise you.  (Psalm 63:3)