Check out the list of websites where you can occasionally experience an issue with the Grammarly browser extension.
At this time Grammarly doesn't initiate in Gmail if your interface is set to a language that uses a right-to-left script. To change your interface in Gmail to English, please follow these steps.
If that is not the case, please clear your browser's cache as described in this article.
Please rest assured that our team is aware of the issue. Unfortunately, we don’t have an estimated timeframe for resolution at this point.
In the meantime, please switch off the Show phrasal predictions feature by clicking the G icon in the upper right corner of the toolbar:
At this time, Grammarly's extension doesn't check the subject line of emails being composed in Gmail.
As a workaround, we suggest that you copy the subject line and paste it into the body of the email for Grammarly to check it, and then copy the text back to the subject line.
Please make sure there are no footnotes and tables in your document. Unfortunately, we’re experiencing some compatibility issues with Google Docs documents that contain footnotes and tables.
As a workaround, we recommend removing them and adding back after editing your document with Grammarly.
If your document doesn’t contain any footnotes or tables, however, and you don’t see Grammarly underlines, please clear your browser's cache as described in this article.
At this time, the advanced suggestions are not available in Google Docs on Safari, Firefox, and Edge. If you use Chrome, check out this article.
At this time, documents of five pages or more may slow down Grammarly’s performance. We are working on extending this limitation.
At this time, the plagiarism checker is not available in Google Docs. As a workaround, we suggest checking your text for plagiarism in the Grammarly Editor or our desktop app.
The Grammarly browser extension works with the status update box, comments, and chat on Facebook. However, the extension doesn’t check your writing in the notes field at this time.
Grammarly works with Messages on Facebook only in Chrome. Unfortunately, other browsers are not supported at this time. To check your writing in Messages, go to https://www.facebook.com/messages and open any message. You should then see the Grammarly icon in the bottom right corner of a text field.
Our technical team is aware of this problem, but unfortunately, we don’t currently have a quick fix.
On WordPress, you can use Grammarly if you access WordPress from the /wp-admin page.
Also, if you switch to the classic editor, Grammarly should work there as well.
At this time, Grammarly does not initialize in HTML mode in the Microsoft Outlook Web App.
As a workaround, please click on More ( three dots) as shown in the screenshot below, and select Switch to plain text:

Alternatively, you can install Grammarly for Microsoft Office (available for Windows OS) to check emails in Microsoft Outlook.