Problem with sending e-mail

There's a problem. Sending mail when a new user registers stops working.

Detailed.
Version CB 2.4.6 free. After CB installation and configuration everything works correctly. Mail is sent when a new user is registered, everything works fine and beautiful.
After an indefinite period of time (a day or two days) - sending mail does not work when registering a new user.
Joomla does not give out errors. Mail on the site works when testing or sending from the contacts menu.
If you uninstall CB and reconfigure user registration to internal joomla means - everything works. Mail is sent when you register a new user.
New CB reinstallation and configuration - everything works correctly again. Several days pass - mail is not sent again when a new user registers.

Is this how it should be for the free version? Should the CB 2.4.6 version always work correctly or is it limited in time?
I would appreciate some advice.

Just to be clear there isn't a free and paid version of CB. CB is just CB. A subscription gives access to plugins and support, but has nothing to do with core functionality of CB.

As for your issue no there isn't some email time bomb in CB. Emails tend to stop working like that due to your mail server rejecting sending them or the mail server you're emailing is blocking them as spam. Make a test registration and review your spam folder to see if the email was marked spam. This can happen if you don't change the registration email in CB > Configuration > Registration from generic email as it would mean you'd likely have the same email as millions of other sites.

Thank you for the answer.

Checking mail is what I do with the test registration.

At test registration CB gives a message
"Sign Up Complete!
An email with further instructions on how to complete your sign up has been sent to the email address you provided...." But the registration letter doesn't come and you can't see it in Logs.

Asked the hoster a question, he answered:
>I:Is there a blocking of outgoing spam on the mail server ? I mean, can the registration email be considered as spam and blocked?
>H:No. No.

>I:In DirectAdmin under Mail Reports / Logs, should I see the emails sent when a new user registers?
>H:Yes, if your site code works properly. But it does not work properly.

Yes, it is also important, if now the site is deployed to the localhost from the backcopy site, the mail works as usual. User registration in CB also works. SMTP settings remain the same.

We're using well known PHPMailer library. The API is not returning any errors otherwise you'd see those errors output by CB. This means it's being sent to the mail server successfully. Review your SMTP configuration carefully in Joomla global configuration and be sure it's correct.

SMTP working fine on your localhost and working temporarily on your live host suggests a problem with your server. Check server error logs to see if there's a server error preventing it from reaching your mail server.

No errors were found on the server.

However, the log file of joomla itself contains an error. Could this error be related to the fact that CB can't reach the mail server?

Not likely, but the default language plugin does not appear to be loaded. Ensure "Default language (English)" in CB > Plugin Management is Published and its access is set to Public.

Are you using a non-English Joomla language plugin while using only English in CB? That could also be a possible cause of the warning if CB is trying to match Joomlas language and you don't have a CB language plugin to match Joomla installed.

Only reason for the registration email to not send without errors is either emails are turned off under CB > Configuration > Integrations or the registration email subject or body is empty in CB > Configuration > Registration or the language strings used for registration email subject or body are translated to an empty string for whatever reason.