I am getting this error from your insight core plugin.
https://api.insightstud.io/update/tractor/patcher.json failed to load
This causes all of the websites backend pages to run and load very slowly. This just started in the last day or two and had worked fine up until then.
I'm waiting answer from support, but found a solution, maybe this can help you.
File to edit is "insight-core.php"
Attached files: Screenshot_12.jpg
Thank for your help. That is right section to disable purchase code checking.