Sometimes a model appears offline in Chaturfier, while they are broadcasting on Chaturbate. Even though online-detection concerning region blocked areas has been significantly improved since version 3.5, it may still happen that these models are blocking the locations that Chaturfier is tracking from (Central Europe and East US). The result is that Chaturfier cannot see these models and you will also not receive online notifications for them.
Besides the reason in the previous question, it is also possible that some broadcasters chose to have "appear on network sites" off in their Chaturbate settings. Chaturfier respects this choice, but still provides a minimal and diminished profile of these broadcasters, so that its users can add alerts and be notified.
However, when these broadcasters are not very popular, for technical reasons, it is difficult to track them successfully and it is possible you will not receive a notification when they go live.
Chaturfier's outgoing emails are signed, encrypted, secured and authenticated with DKIM, SPF, DMARC and are explicitly opt-in. Chaturfier never sends SPAM emails! Despite all this, there are still Mail Transfer Agents and email providers that are under the impression that Chaturfier's emails are SPAM, and will actively block emails before they reach you. Usually the blocking of emails is system-wide (at your mail provider) and of temporary nature.
As mentioned before, it appears that certain mail providers are very stubborn in respecting all these email security protocols. Particularly web.de and gmx.de (and gmx.com, gmx.net, gmx.co.uk, etc), to name just a few, seem unable to follow aforementioned email security standards.
Besides the measures that have already been taken, there is not much that Chaturfier can do about blocked emails. When email delivery problems occur, Chaturfier will register this and you will be notified with a message on this website. The message will explain exactly why email could not be delivered and if the problem is of temporary nature or permanent.
If you are regularly experiencing problems with email, Chaturfier's advice is simply this: be patient and wait for the block to be lifted by your mail provider, or change mail providers (Gmail always works well) or change alert channels. There are options...
Normally session details are retained for a maximum of 4 weeks. For sessions that had less than a maximum of 50 users, the details will be retained for only 24 hours at most.
Online but in private or hidden show, or away.
Online but state unknown, these are broadcasters that have "appear on network sites" off in their settings.
Offline, not broadcasting.
Broadcaster has been deleted, because the account has been abandoned, they opted out of Chaturfier, or they have been banned from Chaturfier (only in very rare cases).
Chaturfier's ranking rewards a broadcaster's popularity and visibility. The ranking score is composed of several factors, including followers, average viewers and online duration, plus several internal factors such as number of defined alerts, for example. Over time the score will degrade and if a model does not regularly broadcast, they will drop in ranking. Scores and rankings are calculated and updated daily.
Chaturfier updates and tracks most broadcasters every minute. This makes sure you will receive those online notifications as fast as possible. However, statistical data, such as number of viewers and current position is delayed. This is how Chaturbate provides this info.