Connection problem with ajp between Apache/2.4.37 (centos 8) and tomcat 9.0.41 (503, service unavailable) AH00896 error

Question

This is the httpd.conf

Listen 80 
ProxyPass /ajpsubdir ajp://127.0.0.1:8009 secret="mysecret"
ProxyPassReverse /ajpsubdir ajp://127.0.0.1:8009 secret="mysecret"

this is the tomcat/conf/server.conf

 <Connector protocol="AJP/1.3"
               address="::1"
               port="8009"
               redirectPort="8443" secretRequired="true" secret="mysecret" />

On http://127.0.0.1/ajpsubdir

I get the error

503, service Service Unavailable.

mod_js seems to be started correctly in mod_jk.log

[Wed Jan 13 20:40:15 2021] [29351:139672606480704] [info] init_jk::mod_jk.c (3591): mod_jk/1.2.48 initialized

Apache error.log

[proxy_ajp:error] [pid 29623:tid 140400610215680] [client 94.36.170.148:1128] AH00896: failed to make connection to backend: 127.0.0.1

Any ideas ?

Thx