I checked your web-site (staging) again and it works ok. Child-theme installed but it is almost clear so we think that the reason was in your child-theme. If you don’t think so, please, create such error with parent theme and send us a link. (for this you may simply switch to parent theme and import your origin theme options (you may export it on origin site in next steps Theme Options -> Import/Export section).
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.