Janusseal App not starting in Firefox version 95.0

Problem is not occurring when tested at 14/Dec/2021 07:30 AEDT with Firefox v95.0.

Firefox version 95.0 appears to have problems loading Office web add-ins like Janusseal App for Outlook.

When attempting to bring up Janusseal App in the side pane when composing a new message, an Add-in Error is shown in yellow stating:

Something went wrong and we couldn't start this add-in. Please try again later or contact your system administrator.

This error also appears with other Office add-ins and is due to an underlying problem in Firefox 95 and Exchange Online.

Firefox 95 is preventing the download of the crucial Office javascript file due to a security issue it perceives with the HTTPS connection to https://appsforoffice.microsoft.com where the file is hosted.


Other error observed when an end-user attempts to send a message from Firefox, in the notifications area of the message bar:

We're sorry, we couldn't access Janusseal App. Make sure you have a network connection. If the problem continues, please try again later.

Article Information
fixed issue
Date created: 
13 Dec, 2021
Last updated: 
14 Dec, 2021 07:28
More Information: 

The same issue is occurring for other Office add-ins like Microsoft's My Templates and Viva Insights, so it is a common issue when using Firefox 95 with Office web add-ins.


Janusnet has found that Firefox 95.0 is preventing download of a crucial javascript file from Microsoft:

The is the "Office javascript" file that every Office web add-in like Janusseal App for Outlook requires to be able to operate.

The link above works fine in Edge and Chrome, but fails in Firefox 95 with error

An error occurred during a connection to appsforoffice.microsoft.com. The OCSP response does not include a status for the certificate being verified.

We are investigating if there is any settings work-around in Firefox to avoid this check for the short term.

We have reported this OCSP error to Microsoft and are awaiting a response from them.


Recommend end-users use an alternative browser while Janusnet continues investigation.

Applies To
Janusseal App for Outlook