Hello Friends, first of all I apologize for my bad English.
I had the same problem with Ionos and the solution with this provider is very simple, I am speaking to those of you who have a VPS server contracted with Ionos.
In principle I have to tell you that when you hire a VPS in Ionos it comes by default with port 25 closed, which is one of the main reasons for not being able to work with mail in Plesk.
Why is this? This is because as there is currently so much spam spam traffic, Ionos has control only over the traffic that they control, but if the mail is controlled directly through the VPS server, they no longer have No control and there will be people who use the server to send SPAM and there is also a greater risk that a hacker hacks the VPS and sends emails from your VPS, for this reason if you do not say anything to those of Ionos, they do not warn you of this and there are actually fewer problems.
In the Ionos panel when you have a VPS, you can create up to 2000 free email accounts with a size of 2 gigabytes each account, if you can choose this option it is much better than creating your email accounts on the server, first because Ionos They are the ones who watch that nobody hacks your email, or sends emails from your server and also if you put the email on the server, you may find the problem that Gmail and Hotmail send your emails to SPAM, which does not happen if you create your email accounts in the Ionos panel instead of on your server
If after all you decide to put your email accounts on your Plesk server you can solve the problem in the following way:
The first thing you have to do is contact Ionos customer service in your country and ask them to open port 25 for you, for this they do not put any problem and they will do it for you in a few minutes.
The next step is to go to your Ionos panel and enter the domain where you want to put those emails and within the domain you must create a subdomain, for example you go to the domain www.example.com and create a subdomain called mail.example. com
Then you enter that subdomain and you are going to adjust the DNS of that subdomain.
Here you must add two new records, one of type A:
Type: A name of the host: mail and in value you must put the I.P of your server, for example: 123.456.789.123
The next record to create is of type MX:
Type: MX hostname: mail and in value you must put: mail.example.com
When generating these new records, it will tell you that they are not compatible with the email records you have and to delete them, as that is correct.
With these steps you have already redirected the mail to your server, now you only have to create your email accounts on your server and configure the mail on your devices.
I hope I have been of help, but from my experience with the mail it is better if you can make it stay in the Ionos panel, you will have less problems.
Greetings.
I had the same problem with Ionos and the solution with this provider is very simple, I am speaking to those of you who have a VPS server contracted with Ionos.
In principle I have to tell you that when you hire a VPS in Ionos it comes by default with port 25 closed, which is one of the main reasons for not being able to work with mail in Plesk.
Why is this? This is because as there is currently so much spam spam traffic, Ionos has control only over the traffic that they control, but if the mail is controlled directly through the VPS server, they no longer have No control and there will be people who use the server to send SPAM and there is also a greater risk that a hacker hacks the VPS and sends emails from your VPS, for this reason if you do not say anything to those of Ionos, they do not warn you of this and there are actually fewer problems.
In the Ionos panel when you have a VPS, you can create up to 2000 free email accounts with a size of 2 gigabytes each account, if you can choose this option it is much better than creating your email accounts on the server, first because Ionos They are the ones who watch that nobody hacks your email, or sends emails from your server and also if you put the email on the server, you may find the problem that Gmail and Hotmail send your emails to SPAM, which does not happen if you create your email accounts in the Ionos panel instead of on your server
If after all you decide to put your email accounts on your Plesk server you can solve the problem in the following way:
The first thing you have to do is contact Ionos customer service in your country and ask them to open port 25 for you, for this they do not put any problem and they will do it for you in a few minutes.
The next step is to go to your Ionos panel and enter the domain where you want to put those emails and within the domain you must create a subdomain, for example you go to the domain www.example.com and create a subdomain called mail.example. com
Then you enter that subdomain and you are going to adjust the DNS of that subdomain.
Here you must add two new records, one of type A:
Type: A name of the host: mail and in value you must put the I.P of your server, for example: 123.456.789.123
The next record to create is of type MX:
Type: MX hostname: mail and in value you must put: mail.example.com
When generating these new records, it will tell you that they are not compatible with the email records you have and to delete them, as that is correct.
With these steps you have already redirected the mail to your server, now you only have to create your email accounts on your server and configure the mail on your devices.
I hope I have been of help, but from my experience with the mail it is better if you can make it stay in the Ionos panel, you will have less problems.
Greetings.