Issue After Upgrading to Paid Plugin – Unable to Modify Attributes

I recently upgraded to the paid version of Varations plugin, after previously using the free version without any issues. However, since the upgrade, I am no longer able to modify or add anything under “Attributes.” Additionally, I cannot save any settings, which was not a problem with the free version.

Could you please check what might be causing this issue? I would appreciate your assistance in resolving it as soon as possible.