Rocket League Activate Not Working: Players Report Problems Linking Epic Games Accounts

Rocket League's Activate page not working has prevented many of the new players jumping into the game in the wake of its free-to-play launch from linking their Epic Games accounts. This has in turn prevented them from playing car soccer to their hearts' content.
Good morning! All services including Friend invites are operating normally. We will continue to monitor and alert here if that changes. ⚽️?️??
— Rocket League (@RocketLeague) September 17, 2020
Rocket League Activate Not Working: Players Report Problems Linking Epic Games Accounts
Rocket League developer Psyonix and Epic Games themselves have investigated the problem and claimed to have solved it Sept. 17, but players say it is still stopping account linking. Being unable to link the accounts means they can't access their unlocks, match history and more across platforms as advertised.
Some players have reported using the Activate page in different languages has allowed them to link the accounts. One Reddit user said activating through the Portuguese-language activation page worked, requiring only that they translate the Portuguese with their browser.
Unfortunately, further solutions will likely require intervention from either Psyonix or Epic Games support.