When you make an extension for Magento, you may face an issue like this:
Cannot instantiate abstract class Magento\\Framework\\Model\\ResourceModel\\AbstractResource at
Cannot instantiate abstract class Magento\Framework\Model\ResourceModel\AbstractResource in
There are many reasons, but this may be a common case. I give you some tips so you can try to fix it yourself.
This often happens when a third-party extension has a default parameter in between the __construct() arguments instead of at the end.
Please check which action you're performing while getting this error. One of the classes involved in this action can have a default parameter in between, like below:
You need to move array $data =  to the last position because it has a default value.