I worked for 3 years in a project in university A and then registered for phd in different university B, stating my actual supervisor as cosupervisor for thesis. I continued and wrote my thesis. Now my supervisor A seems not interested in my thesis. Can I help this situation ??? or leave the idea completely.

Is supervisor A from University A. What does your supervisor at university B think. Doues your thesis plan include research conducted whilst you were at university A?