Mailster is a part of Joomla which is a PHP based web application. That means: it can not act/run without being triggered and it can not run forever when triggered. This is a technical limitation coming from PHP, not from Mailster or Joomla. Triggering means that somebody accesses the site. During the page load Mailster is handling the jobs to do (mail retrieving/sending).

Thus mails can only be send/retrieved when somebody is browsing your site, otherwise the delivery is delayed or never done. As your site might not be browsed every few minutes 24x7 we recommend you to use a cronjob that opens the site periodically (e.g. by a command-line tool like wget).

If you cannot create a cron job we can offer you to host a job for you on a server of us (in return for a small yearly fee). Click here to learn more.

Please read the section about send errors in our troubleshooting documentation.

The mail queue shows all emails that are planned for sending. The ones that are locked (red lock symbol) are already prepared for sending. Every outgoing email goes through this status. So there is nothing to worry about - all emails will go out at some point.

We defintely want to. But as our ressources are limited all translations (except English and German) are made by volunteers.
If you are a native speaker in a language that we do not support yet and are interested in helping us please visit our translation project on Transifex. Simply register at the site and request to be added to the project / language.

The reason is that the link to the image is relative (images/banners/MailsterBannerNewsletter.jpg) and does not contain the URL (http://www....) the image has to be retrieved from. You have to make sure that the URL is included.
A potential pitfall is the WYSIWYG-editor in Joomla - some editors strip out the URL of the site ending up in a relative link. This happens e.g. with the JCE editor. You should be able to disable this behaviour in the editor's settings.

You might get an error message like this when checking the connection settings: "Certificate failure for [server] Server name does not match certificate" or "Certificate failure for [server] unable to get local issuer certificate".

If you use your own mailing server (with a self-signed certificate) you need to deactivate the automated certificate check to get a connection to your inbox. Do this by adding the following line in the special parameter box: /novalidate-cert

Gmail / Google GSuite requires some additional settings before they allow "regular" email connections.This is described here: https://support.google.com/accounts/answer/6010255?hl=en

Your server needs the PHP IMAP extension installed (see system requirements), otherwise Mailster can not work at all. There is nothing that we can do about that, you need to contact your hoster and see whether they can enable/install the PHP IMAP extension.
If that is not possible you need to use a different hoster providing a more suitable environment.
Please note that it does not matter whether you want to use IMAP or POP3 for accessing the mailing list inbox. You need the extension in both cases, it is not specific to the IMAP protocol.

You probably have a Javascript error (read here how to display such errors) in your browser. This might be caused by another extension loading the same Javascript library (jQuery) in an "destructive" way. An example for this problem is the GCalendar component in the version 2.6.3 (and earlier). In that case you need to upgrade to a newer (2.6.4+) version.

Your webhoster uses a PHP configuration (typically mod_php) that only allows a certain number of processes to be opened through a library of the PHP IMAP module. In shared environments this can lead to the above error when Mailster opens the inbox throught the PHP function imap_open.
This problem is caused by the webhoster's environment - you need to talk with your hoster whether they can solve the issue for you. If they can't do this you are not able to execute Mailster in that environment.

A white screen appears when there was an error 500, which is a code for "internal server error". To be able to see the actual error message you need to enable the error reporting in Joomla's global configuration. Set this setting to "Maximum".

What if you cannot login to the site?
In case Mailster is the component making trouble (e.g. because of the above described fatal out of memory error): don't worry, there is a way to login to the site by telling the Mailster plugin to stop it's execution. The Email Forwarder plugin can be disabled by putting a file "no_mst_plg_exec.txt" or "no_mst_plg_exec" into the directory [joomla]/administrator/components/com_mailster. It is not important what is in the file, but the filename has to be exactly one of the both mentioned variants.
After creating the file you should be able to login to access your site's backend, again.

Then deactivate the Mailster mail (email forwarder) plugin in the Plugin Manager (putting the status to "disabled").

If you already know that this problem is due to a very large email sitting in the inbox: directly navigate to your mailing list's settings, in the "Tools" section and use the link to delete the first email from the inbox. After fixing the error do not forget to reactivate the mail plugin.

Your issue is very likely coming from a large email causing an PHP out of memory error. This is resulting from the fact that every PHP environment has a memory limit. This limit is hit when the email is tried to be retrieved from the mail server.

Please remove this email from the mailing list in question. Either through a mail webfrontend or with the "Delete first email in inbox" tool the "Tools" section in the mailing list's settings.

In order to prevent have this happen in the future:

• Raise the PHP memory limit. Your hoster can help you with that.
• Introduce a maximum email size for Mailster. You can find this setting in the "List behaviour" tab of the mailing lists settings. If larger emails are in the inbox, Mailster will not try to process them but simply delete it and tell the sender what happened.

This appears due to your PHP environment settings. The messages are not critical in any way. Those errors are just notifying to use better coding standard. You can either disable this through the php.ini configuration or by setting Joomla's error level configuration to "Normal".

To modify PHP environment's settings, see this article for help: Disabling Strict Standards in PHP 5.4. If this is beyond your level of technical comfort you should contact your hoster to help you with that.

Notices are the least important of warnings that a PHP environment will report. According to the official PHP website, notices are generated when: "the script encountered something that could indicate an error, but could also happen in the normal course of running a script."

We generally recommend to disable the error reporting on your Joomla Site.

Another approach is to modify PHP environment's settings, see this article for help: How do I turn off PHP notices?. If this is beyond your level of technical comfort you should contact your hoster to help you with that.