These types of errors are normally caused by misconfiguration of your /etc/apt/sources.list.
In this example on Debian 10, if you didn't complete the install correctly, you will have no repos enabled and only rely on CDROM.
"Package wget is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source.
E: Package 'wget' ha........
Jul 3 22:12:17mailserver postfix/smtpd[6195]: fatal: no SASL authentication mechanisms
Jul 3 22:12:18mailserver postfix/master[4881]: warning: process /usr/libexec/postfix/smtpd pid 6195 exit status 1
Jul 3 22:12:18mailserver postfix/master[4881]: warning: /usr/libexec/postfix/smtpd: bad command startup -- throttling
This only ever happens in my experience when the authentication method is actually Dovecot. Usually the problem........
Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, root@localhost and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Apache/2.2.15 (CentOS) Server at testdomain.com Port 80........
An error occurred during a connection to site.com. SSL received a record that exceeded the maximum permissible length. (Error code: ssl_error_rx_record_too_long)
The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
Please contact the website owners to inform them of this problem.
When the above happens in our experience it is a misconfiguration of........