Managed to reduce to a fairly small sample:
!define AWSPuml https://raw.githubusercontent.com/awslabs/aws-icons-for-plantuml/v11.1/dist
Alice -> Bob
If remove the include AWSPuml/AWSCommon.puml it works.
Or if remove the <code></code> lines it also works
Cant see anything obvious in that include to cause issues.
PlantUML version 1.2021.9 (Sun Jul 25 20:13:56 AEST 2021)
(GPL source distribution)
Java Runtime: OpenJDK Runtime Environment
JVM: OpenJDK 64-Bit Server VM
Default Encoding: UTF-8
Dot version: dot - graphviz version 2.48.0 (20210717.1556)
Installation seems OK. File generation OK