How to fix : FSL_HELO_BARE_IP_2

[milsou]

Hello everyone

In test-mail.com for my domaine I have a 6/10... I need to solve this problem :

FSL_HELO_BARE_IP_2 IP used in the HELO request
The hostname should be a domain name, not an IP address

And this :

RDNS_NONE Delivered to internal network by a host with no rDNS
This may be a false-positive, please check the reverse DNS test below to confirm or not this issue

Can someone tell me please how to fix ?
Thanks