ReflectionException occured on faryshta extension in yii2

I am using Yii2 basic application template and Faryshta/yii2-disable-submit-button extension. I have hosted the software files on my VPS server. I have installed composer and also updated. When I start to run the application it shows the error as below:

Class app\assets\DisableSubmitButtonsAsset does not exist

that means that you are missing a file. Unless you post the full error stack trace we can not say which part of your code needs that file. Make sure you have uploaded all files to the correct places on your VPS.