I just used this guide to install the Goobi Viewer.
I noticed that under the Connector - (OAI & SRU) subheading, there was a typo in the command (I presume so atleast):
Isn’t the correct path
/etc/tomcat9/Catalina/localhost/M2M.xml as it says in the text, and not
/etc/tomcat/Catalina/localhost/M2M.xml as it says in the code example? The ‘9’ is missing from tomcat9.