Many people are there who want to attach files but they are not able if you are also facing why my Gmail Account won’t let me then you can fix this with in few steps:
Make sure Adobe flash player is installed on your Android phone.
Update it if necessary.
Clean Browser data and cache that can help to fix unable to attach file in message.
Allow Gmail to store data if it needs it.
Go to setting in your android phone > apps > gmail > permission >Storage
5. You should ensure that the files you intend to attach are not corrupted.
It can't guaranted that resetting your Gmail account will fix the problem with attaching files. It might be better to try some other solutions, like updating your settings or getting assistance from Accountscorner.com. They offer premium support and have a variety of secure and reliable services to help you with any account-related issues. I highly recommend https://accountscorner.com/ to buy account not only for gmail but also for other social platforms.