Apple ID in Xcode 6.2 and Mac OS 10.9.5

many error message from Mac software Servers present only the first part of the message, essentially,

"Not Found..."

the second part, out it were presented, would read

"...with the the Apple-ID proffered or NO Apple-ID..."

and in your case there should be a third section that reads:

"...or with SSL encryption, which is inadequate"

SSL to TLS:

In 2015, researchers discovered that Secure Socket Layer (SSL) Internet encryption was not nearly as secure as was thought, and needed to be replaced. Internet encryption quickly moved to Transport Layer Security (TLS) which was rapidly deployed across the Internet.

This was possible because advances in Layered Network Architecture had separated out Transport Layer as separate entity, and the entire model had become more mature. Open Transport software, which offered TLS, was readily available to be pressed into service

Over time, sites tightened requirements for what was acceptable for encryption.

Apple issued Safari version 9 in 10.11 El Capitan version of MacOS, which included TLS encryption. It was later provided by Security Update into the two previous versions of MacOS. 10.10 Yosemite and 10.9 Mavericks, PROVIDED you applied all available software updates.

MacOS versions older than those can not make a lot of secure [httpS:] connections on the Internet, because by todays standards, your proffered SSL encryption is considered inadequate.

Mac OS X 10.9 Mavericks was released in October 2013, over fifteen years ago.

The current version of macOS is 26.5.1. and spans twelve generational releases of the OS since Mavericks.

Xcode 6.2 was released in March 2015, more than eleven years ago.

The current version of Xcode is 26.5.

The point is, there have been lots of changes made to both the OS and the application since the versions you are using. Internet website security and access has also evolved. The protocols that were commonly used eleven years ago have been superseded by ones that are both newer and more secure.

I don't think you're going to be getting access to the old websites by way of that old macOS and Xcode software.

Having said all this, to answer your question:

User_Apple_Disscussion wrote:

How can I fix this error in Mac OS Mavericks and Xocde 6.2 by updating Mac OS?

Maybe.

You may have to upgrade to the newest OS that your Mac can run, and even that may not be good enough. But it's worth a try. And you may also have to upgrade Xcode to the newest version available for the OS that you settle on for your Mac.

Update macOS on Mac - Apple Support

Parsing the Error Response Code | Apple Developer Documentation

this will help