haproxyng working with munin-run but not in munin-node

[Sokan311]

Thanks for this very usefull project.
I have the following problem

munin-node -v
This is munin-node v2.0.24

cat /proc/version
Linux version 3.10.0-1127.8.2.el7.x86_64 (mockbuild@kbuilder.bsys.centos.org) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-39) (GCC) ) #1 SMP Tue May 12 16:57:42 UTC 2020

ls -alh /run/haproxy/haproxy.sock
srwxrwxrwx. 1 root root 0 May 22 15:47 /run/haproxy/haproxy.sock

cat /etc/munin/plugin-conf.d/haproxy
[haproxyng]
user root
env.socket /run/haproxy/haproxy.sock

"munin-run haproxyng" works fine but, when the plugin is called within munin-node

2020/05/26-07:55:04 [68350] Error output from haproxyng:
2020/05/26-07:55:04 [68350] do_config: Cannot connect to socket /run/haproxy/haproxy.sock at /etc/munin/plugins/haproxyng line 153.
2020/05/26-07:55:04 [68350] main::get_data() called at /etc/munin/plugins/haproxyng line 1028
2020/05/26-07:55:04 [68350] main::do_config() called at (eval 12) line 1
2020/05/26-07:55:04 [68350] eval 'do_config();' called at /etc/munin/plugins/haproxyng line 144
2020/05/26-07:55:04 [68350] at /etc/munin/plugins/haproxyng line 144.
2020/05/26-07:55:04 [68350] Service 'haproxyng' exited with status 13/0.
2020/05/26-07:55:05 [68350] Error output from haproxyng:
2020/05/26-07:55:05 [68350] do_fetch: Cannot connect to socket /run/haproxy/haproxy.sock at /etc/munin/plugins/haproxyng line 153.
2020/05/26-07:55:05 [68350] main::get_data() called at /etc/munin/plugins/haproxyng line 1014
2020/05/26-07:55:05 [68350] main::do_fetch() called at (eval 12) line 1
2020/05/26-07:55:05 [68350] eval 'do_fetch();' called at /etc/munin/plugins/haproxyng line 144
2020/05/26-07:55:05 [68350] at /etc/munin/plugins/haproxyng line 144.
2020/05/26-07:55:05 [68350] Service 'haproxyng' exited with status 13/0.