What message?

Install adblockers to help slow down many such messages.

Every now and then, run your anti-virus scan using the Full option.

You should also run a malware scan as well. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

I have all these and all work well . It is being solved after I installed ( anti-malware) thank you but another question I want to ask : I notice when use Firefox to search beside the links of pages, icons appear. This feature I have never seen before

Those are part of the title. Don't worry about them.

Yes helpful, and many thanks to you, but why before three days or one week I did not notice those and Google search are never appeared  ?

I don't know. It could be one of your add-ons. It could be the web page.