Opening the apps stopped writing

Sir, everything is fine if I do a live test on apps. But when I build apps and install them on my mobile phone, “App Stoped” is written. Sir and I have built apps many times before but then this was not a problem. Please help me ??Screenshot_20191114-181319

Please provide more info, what do you do on start, are you using extensions, you execute blocks of extensions on start?

how sir, please help

Only answers to my questions:
What do you do on start?
Are you using extensions?
You execute blocks of extensions on start?

sir, i used extension.

You can use the following guide, How to ask questions / ¿Cómo hacer preguntas? if you are not sure what information to attach ,so that we can help you.

Share your blocks Screenshort.

If you used an extension we cannot help you with errors of the extension.