What is the problem?
Your contacts don't see the messages you send them from Holded because they receive them in the spam folder.
Most likely, the recipient's mail server does not have your sending server address registered as an accepted source.
How to resolve this
If the recipients of your messages do not accept to receive mail from your server, you can configure your email sender policies and verify domain ownership using theSender Policy Framework ( SPF).
Log into your web domain manager, such as Godaddy or Cdmon, and go to the DNS records section to configure the SPF.
Generate a new DNS record and select the TXT/SPF option.
Enter the details as instructed by your domain provider, which usually follow these conventions:
Name: the host name for the record. Type @ to place the SPF record in your root domain, or enter a prefix; for example, mail.
Value: the SPF rule that will be applied to indicate which emails are authorised by your server.
TTL: time period for which the server should cache information; the default setting is 1 hour.
Add the Holded IP: 220.127.116.11. This ensures that recipients will accept messages sent from this address.
The SPF rule
With an example you can better understand the parts of the SPF value:
v=spf1 mx a ptr ip4:18.104.22.168 include: server ~all
v indicates the version of SPF used; in the example version 1
a indicates the DNS domain record; in the example, the version a
ptr authorises the hosts under the domain in question
ip4 V4 IP addresses
include extra servers from which emails go out
~all blocks machines that have not been explicitly authorised
You can find more information about the SPF record syntax in this link.
Sender Policy Framework (SPF) stands for Sender Policy Framework.
It is a system of protection against address forgery when sending e-mails.
Its function is to identify the SMTP mail servers that are authorised to transport messages via the Domain Name Records (DNS).
DNS stands for Domain Name System.
It is an Internet protocol whose function is to resolve domain names, translating them into IP addresses. Each domain is assigned a DNS.
IP stands for Internet Protocol, which means Internet Protocol.
It is a unique address that identifies a device on the Internet or on a local network. In essence, IP addresses are the identifier that allows information to be sent between devices on a network.