A message saying, “The maximum number of free accounts have been activated”, is discussed in the support document: https://support.apple.com/101661
Apple apparently limits excessive Apple Account creation, or iCloud activation of web-created accounts, on any one device per year (presumably a 12-month period). Your options are:
1. Use a different account that has already been set up on a device previously,.
2. Set up the account on a different device that hasn’t reached this limit (you can then use it on the device that displayed the message previously).
3. Wait until the time limit has passed.
You are welcome to contact Apple and check if they are willing to reset the count for you:
This support article has various country telephone numbers for contacting Apple for support and service ➔ https://support.apple.com/106932 Scroll down to “Connect with live support”. If your country is not in the list, go to the “Other countries” entry at the end of the list and click on the “options” link. Not every country has telephone support, and phone numbers may only work when calling from the same country.
For chat, you can try using the Apple Support App —> https://apps.apple.com/app/apple-support/id1130498044
For chat help with a USA Apple Account —>
https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0998&symptom_id=20198