I am getting the exact same issue as Ghaith. Is it a PHP version issue. I installed the plugin on a different site as a test running PHP v7.4.9 and works fine, but when I installed it on another site running PHP version 7.1.33 I get the exact same error above.
I have uninstalled – re-installed and deactivated as suggestions above, with no luck!
Do you have any feed back or a solution to this issue??
Thank you in advance