Installation de la CS6

The chat agent is correct... Adobe no longer suppports that program from 2012

>installation file tells me that my activation key has expired

A CS6 serial number should not expire... HOWEVER

-where did you buy CS6... direct from Adobe or from some other vendor?

-I have read that some people who bought from a school DID have a time limit, which was between the school and Adobe, so the people who bought from that school DID have a time limit

You say re-install... so could the message have been that you had used up your 2 activations?

IF you have used up your 2 activations the ONLY support Adobe gives is to reset the activation count

When you can't deactivate a serial number
BE SURE TO ONLY ASK FOR ACTIVATION SUPPORT TO ADJUST YOUR ACTIVATION COUNT
You may need to PERSIST or TRY AGAIN to find a support agent with more experience

This space is provided by Adobe, but it is not Adobe support
Sorry, nobody here can help with an account or payment problem
This is a public forum, you need the link to Adobe support, not other users
Be sure to remain signed in with your Adobe ID before accessing the link
Do be aware that Adobe's staffing is impacted by the virus, so wait times are long
-you MUST make sure that your browser does NOT block ads, scripts, or pop-ups
-you MUST also allow 'cookies' in your web browser for the link to work
This link will go directly to the chat option
Type "Agent" in the chat box to bypass the chatbot and be connected to a person
-Meaning type in the word Agent without the quote " " marks
https://helpx.adobe.com/contact.html?rghtup=autoOpen
- or https://helpx.adobe.com/contact/phone.html
.
Adobe does NOT do support by email, so beware of answering anyone who sends you a private message
-click for more information about scammers https://tinyurl.com/10791730

Try see if you can talk to an Adobe agent. You can connect via the text chat. Mae sure you type real aget at the start to ensure you are connected to a real person:
https://helpx.adobe.com/contact.html