As the webmaster of your own site, you are responsible for maintaining the accessibility of the content on your pages. If your site has any accessibility issues (508 errors), it will be clearly flagged in the User Site Center, which you can access via the My Website icon at the top of any page in your user portal then click on the Manage Site button at the top of the page.
The View Issues button will take you the Site Health Report where all pages with errors are listed.
Additionally, when you are in the edit mode for a page, the errors will be flagged on the modules with the issue.
Fixing 508 Errors
The question mark icon in the error flag on the modules will take you to our Webmaster Guide to 508 Errors article. Fixing errors is a matter of understanding the error and working with the module with the error. For example, the image above indicates that you must add alternative text to the image used in the image module. To fix these errors, you need to understand how to work with the individual modules. Please refer to the List of Modules and their Functions article for more information.