“SG Optimizer needs to be deactive”

I have been using SG Optimizer plus WP Fastest Cache with no issues. Though I migrated my website to a new domain and now WPFC asks me to deactivate SG Optimizer in order to be able enable/submit settings. Disabled SG Optimizer and was able to enable/submit WPFC, it wrote every code into .htaccess, then I re-activated SG Optimizer, but still afraid that WPFC may not be working, went back and hitted ‘Submit’ button and it said the same message (when SG Optimizer was activated): “SG Optimizer needs to be deactive”. How to proceed? Thanks in advance!