APK built error problem

[I_Am_The_Bong]

Can any one plz tell me what is this Problem

I have faced this problem two times but the reason was different. Reason 1:- For some imported extensions. Reason 2:- For some non-completed blocks. Solutions:- At first check your all blocks, if there are any duplicate blocks then simply delete them. [screenshot (44)] If you have no error in blocks then try the second method, remove one extension and try to export your app, if you get this same error then try this repeatedly.