I don't have Avast, even if it installs it now, it wouldn't give me that error.
What I can ask for, which I would appreciate, is your help in doing this, in case this message appears again. To do this, follow these instructions: https://businesshelp.avast.com/Content/Products/General_Help/SampleSubmission/SubmittingFalsePositives.htm
I researched ways to contact them in this regard, and these were the only instructions I received on the subject. If anyone knows of anything else that can be done, please let me know.
I actually already did the same thing you suggested. I filled out the Avast form to report a false positive for your website. They say they will review it within the next 48 business hours and update their detection database once the result of the analysis is ready.
Hopefully, they will resolve the matter quickly so everyone can access your site without problems.