WordPress fix Site is Currently unable to Handle This Request

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Site is Currently unable to Handle This Request, by ogami

Hello people.
I’ve been trying to remove “steam24/wordpress” from my “steam24.ir” URL, using the “Method II (With URL change)” according to the link below.

https://codex.wordpress.org/Giving_WordPress_Its_Own_Directory

But every time I change my settings I can’t get back in my dashboard settings, and I have to delete the Database, delete the wordpress file and reinstall to fix it. I have reinstalled it 5 times now, and I can’t figure what part of it is wrong?

Steam24.ir loads but gives the following error.

“Site is Currently unable to Handle This Request”

Steam24.ir/wordpres/… doesn’t load and gives the 404 missing directory error.

What am I doing wrong? I follow every single step from the method.
https://codex.wordpress.org/Giving_WordPress_Its_Own_Directory

Attached Pictures:
Before Changing the settings
http://s9.picofile.com/file/8318018176/Before_Changing.png
After Changing the settings
http://s9.picofile.com/file/8318018168/After_Changing.png

Thanks in advance.

Site is Currently unable to Handle This Request