Blank gmails can be used in Firefox only

[CHAPLIN]

I send out gmails with an image and formatted text to customers several times a day. A small percent say the get a blank mail. I have narrowed it down to Firefox users. Searching the web there are some clues that this might be due to ADP but I am unfamiliar with the rules system used there. I sent a mail to myself which I opened in Firefox and it is indeed blank. Is there a way to prove this is ADP causing the issue? Just removing the image doesn't help, but removing all formatting allows the message to be seen (but I need the formatting).
Happy to send a copy of the email to anyone interested in helping here.
On this site I find old (2011) similar things, but the solution takes me to solutions that don't seem to exist in current versions of ADP and/or Firefox.

Probably should have done this first. I just removed ADP from my Firefox add-ons and rebooted it and then sent a new gmail to it and it is still blank. I am probably barking up the wrong tree here. Now only hope is someone who visits here can point me to either Firefox or Google for the answer. I am off on the hunt ......

[sbell]

Hi Chaplin!

Thanks for reaching out! Based on the details you provided, it sounds like the issue may be elsewhere since the problem persists when ABP is not installed on Firefox. So you are ten steps ahead on isolating the issue. Maybe try disabling some of your other add ons if any, one by one to see if you notice a difference.

Thanks
Shannon
ABP Support Team