I have installed VMware Server on my computer but whenever I attempt to run the program it opens a webpage and the following message appears “haralds-pc8333 uses an invalid security certificate. The certificate is not trusted because it is self assigned”. Why do I get this message and why do I need to go to this website?

VMware Server uses a web-based interface called Virtual Infrastructure Web Access to administer the virtual machines, which is why you need to visit this web page to interact with VMware Server (you are actually visiting a website hosted on your local computer, and not one on the internet). The message which you are receiving informs you that the secure certificate has been signed by your own computer, rather than a trusted third-party source. This is not a problem for our purposes here, since you trust your own computer which issued the certificate. Therefore, you can safely click through this message and proceed to the VI Web Access Interface. Be aware, if you received the same message, about an invalid security certificate, on a real internet-based website then that would indicate a problem, as you do not trust a server on the internet without a proper, valid security certificate. So, if you see that message when using the internet you should generally not proceed.