Forbidden 403 Error

HI friends I'm Isabella. I have WordPress site today just change theme after then show forbidden 403 messages doesn't have permission access this page anyone help me how to resolve this issus

Try the steps mentioned in the following link:
https://www.wpbeginner.com/wp-tutori...-in-wordpress/
hope that works for you.

In this tutorial, you are going to learn about the reasons that might be liable for a 403 forbidden error in detail and possible solutions that will help you get rid of it. As an example, we will show you how to fix this error on a WordPress site. However, steps would be almost identical on any other CMS or static websites.

It is worth mentioning that 403 errors might differ based on various circumstances. Occasionally, this error can also be a result of a few changes that your hosting company might have made in their system or due to the implementation of some updates smart security system.

Whatever it is, let’s look deeper into the error and find out more details about it. We will then list out various reasons responsible for this error, and the possible solutions for it.

The most common cause for the 403 Forbidden error in WordPress is due to poorly configured security plugins. Many WordPress security plugins can block an IP address only if they believe them to be malicious.

Another possible cause could be a corrupt .htaccess file or incorrect file permissions on your server.

Your WordPress hosting company can sometimes make accidental changes to their server settings. This may result in 403 Forbidden error on your site.

contact your web host open a ticket maybe they can fix

Well, if theme change has caused 403 error, then try reverting back theme change.

I would suggest using an offsite backup system, where you can switch back easily while experimenting. On every change, you can keep a backup copy.
Also, checkout if you can get a staging environment, where you can experiment before implementing on live environment.

The 403 Forbidden Error happens when the web page (or other resource) that you're trying to open in your web browser is a resource that you're not allowed to access. It's called a 403 error because that's the HTTP status code that the web server uses to describe that kind of error.

403 error means you are requesting for the web page and its not available or not able to access that file.
First you can check permission of your files or folders and you can also check your .htaccess file too.

If you are still not able to solve Forbidden Error then you can contact your hostig provider.

The 403 Forbidden Error happens when the web page (or other resource) that you're trying to open in your web browser is a resource that you're not allowed to access. It's called a 403 error because that's the HTTP status code that the web server uses to describe that kind of error.