The TinyMCE editor comes with a built in accessibility checker that scans the current working document for any potential accessibility issues. You can manually trigger this scan by clicking the Accessibility Checker button in the editor toolbar. This will open a popup window which will show potential issues and steps to fix them. 

The accessibility checker will also run when the Active status button is selected and accessibility issues are found. If no issues are present, the checker will not run.

In the event of present issues, selecting the button will scroll your screen back up to the first issue detected, highlight the issue in red, and open a popup describing the problem.

Some issues can be resolved within the popup window. In the example below, an image is missing alt text. Enter the desired text and click Repair to fix the issue.

Other issues will require you to implement the necessary fix within the editor itself. In the example below, text within the document body does not meet accessible color contrast standards. To fix this problem, change the text color to something more suitable within the editor. Rerunning the accessibility checker will find that this issue has been resolved. 

Additionally, if more than one issue exists, you can use the up and down arrows in the popup window to navigate between issues in a document. For more information on each accessibility problem, click the question mark icon. This will redirect you to further documentation on each particular issue.