Yesterday we disabled all legacy API keys for our YOOtheme products. This applies to API keys generated before our website relaunch in July 2018. Those master API keys couldn't be deleted to prevent illegal use. That's why since 2018 a unique API key has to be generated for each client website. This means instead of exposing your master API key to your clients, each client gets its own API key which can be deactivated individually. If you're still using a legacy API key, head over to the Websites tab of your YOOtheme account and create new API keys for your websites.
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