Error loading Smtp Server tab (PLEASE HELP!!!)

[Scippy]

Hi,
in my latest DNN9.10.2 installation I only realized it now that I'm no able to access to SMTP settings. I receive "Error loading Smtp Server tab" and it doesn't allow me to save any smtp settings.

I've no exceptions in Admin Log, but looking at Server Setting-> Logs log.resorces I can see this exception:

2022-04-02 12:21:50.540+02:00 [WEB001][D:14][T:27][ERROR] Dnn.PersonaBar.Servers.Services.ServerSettingsSmtpHostController - System.NullReferenceException: Object reference not set to an instance of an object. at Dnn.PersonaBar.Servers.Services.ServerSettingsSmtpHostController.GetSmtpSettings()

I've tried to manual add SMTP portal and general settings in HOSTSETTINGS table and in PORTALSETTINGS table but DNN still can't send any emails and still I'm no able to access to SMTP settings by PersonaBar.

I don't know what to do anymore, can someone help me?

[Scippy]

YESS! I've Fixed!
It was missing in web.config:
in sectionGroup
<section name="mail" requirePermission="false" type="DotNetNuke.Framework.Providers.ProviderConfigurationHandler, DotNetNuke"/>
in dotnetnuke

<mail defaultProvider="CoreMailProvider">
      <providers>
        <clear/>
        <add name="CoreMailProvider" type="DotNetNuke.Services.Mail.CoreMailProvider, DotNetNuke" hideCoreSettings="False"/>
        <add name="MailKitMailProvider" type="DotNetNuke.Services.Mail.MailKitMailProvider, DotNetNuke" hideCoreSettings="False"/>
      </providers>
    </mail>

Now I'm able to load SMTP server tab and send emails!