Installation fails

[ottlinger]

I just wanted to play with the project ... installation failed even after changing

-RUN apt-get -y -q install curl gnupg
+RUN apt-get -y -q install curl gnupg libcap2-bin

ntopng fails to install:

Setting up libpangocairo-1.0-0:amd64 (1.40.14-1ubuntu0.1) ...
Setting up librrd8:amd64 (1.7.0-1build1) ...
Setting up ntopng (5.7.230820-21352) ...
Creating ntopng group
/var/lib/dpkg/info/ntopng.postinst: 33: /var/lib/dpkg/info/ntopng.postinst: nmap: Operation not permitted
dpkg: error processing package ntopng (--configure):
 installed ntopng package post-installation script subprocess returned error exit status 2
Processing triggers for libc-bin (2.27-3ubuntu1.6) ...
Errors were encountered while processing:
 ntopng
E: Sub-process /usr/bin/dpkg returned an error code (1)
The command '/bin/sh -c apt-get update &&     apt-get -y -q install ntopng' returned a non-zero code: 100
make: *** [Makefile:6: build] Fehler 100