Within Klubs, numerous types of mailings are sent such as invitations, confirmations, as well as membership renewals and also email campaigns.
The tracking of these sent emails can be done in several ways.
Settings - email texts
In Settings, there are about 25 email texts that are used in the various communications.

Each of these mails can have an additional mail address attached to it that then also appears in CC of that mail and thus receives the mail.
Reporting - Email Campaigns
With email campaigns, there is separate reporting.

Campaign reporting with indication of effective sending timing.
Reporting - Profile
For each member, there is also a reporting of mail activity

Through the admin member list to a member's profile and there at the tab
- Email Follow-up
A list of the emails sent to this particular member.
Reporting - Emails
At Admin reports a full report around mail traffic from Klubs.

Reporting with indication of timing for Accepted, Delivery, Opened.
Undelivered mails
For sending the mails from Klubs, we work with a transactional mail system. This is a separate service that guarantees high delivery. Additionally, all mails are personalized with deposit codes (#firstname) to increase this delivery even more.
The non-arrival of mails has nothing/not much to do with the sender, more with the spam settings at the receiver.
Part of the problem lies with the recipient
Outlook, Hotmail, almost all Microsoft mail accounts, have a very high spam sensitivity.
In addition, there is also the issue of control at company accounts or Providers with specific Anti-Spam filters.
Here is some background info around various mail delivery issues:

