What's the PlayFab Extension version and SDK version? If you have trouble upgrading to the latest version, please find the latest version on PlayFab/UnitySDK: Unity C# SDKs for PlayFab (github.com) and you can remove the sdk folder then re-import.
There is a known issue that prevents upgrading to 2.120.211209, please check Cannot update from 2.116 to 2.120 when clicking upgrade button.
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