Related Problems:

• You need to make this file writable before you can save your changes
• To perform the requested action, WordPress needs to access your web server

If you’ve already tried the folder permission 775 or 755 trick but still encountering this error, try the following solutions:

1. Login via SSH
2. Go to the parent folder of your wordpress folder
3. Type the following chown -R username:www-data yourwordpressfolder

If www-data group doesn’t exists, try chown -R username:nobody yourwordpressfolder
Example: chown -R ohnorandom:nobody public_html

4. Then type chmod -R 775 yourwordpressfolder

This should solve the permission problem.