I apologize, I did not post the links correctly in my very first post here:

https://forums.mozillazine.org/viewtopic.php?p=14985444#p14985444

https://community.adobe.com/t5/acroba.../14893786#M480889

https://acrobat.uservoice.com/forums/.../48914657-mozilla-firefox-since-v127-0-cannot-install-anymor

See:

• https://discourse.mozilla.org/t/upgraded-add-on-signatures/129599

I apologize, I did not post the links correctly in my very first post here:

Note, to edit your own thread here look for Edit this question under Question Tools on right and to edit your own reply look for the vertical three dots and Edit this post.

Thank you both for your most quickest and most kindest answers here! :)

Thank you @cor-el , finally someone who pointed me into right direction, that it is the Adobe Corp. problemo...

And, thank you @James for a more clarification how to edit my post here. :) I feel now as a little bit of a clumsy idiot :) , pardon me, but as a novice here, it was a little bit confusing to me during last very late night here..., I was already a terrible tired then, also about all of this postings of mine on 5-6 different forums yesterday, and I obviously overlooked that the right part of the web page here has a perfectly Edit this question option available... In addition, I also remember last night here, that it was confusing for me just one more thing here - because on my very first post here, by following the upper right 3-dots option just beside my just posting post, it was not showing to me at all this Edit this question option, but it only appears as a 3-dots option from my second and any further posts here, but not at all on mine very first post here... Well, in any case I make corrections in my very first post here just right now, and I add now, even the third web link where I also post about all of this problems last night, so now there is even a two different Adobe Corp. online sources where I also post about this particular and serious problem.

All in all, at least I make my diligent "homework" now as some regular user/customer/whatever... :) , and make a note to simply everybody who is a relevant here, so better than that, I simply cannot do... After all, we know now that we all, obviously need to wait only the Adobe Corp., and my further hope is that they will read my posts, so that the next Adobe Acrobat Pro Update will finally fix all this, including this Digital signing problemo.

In the meantime, I want to thank you both guys here for all the help and advice in last two days, and if you do not perhaps have any more suggestions on which more of the Adobe Corp. Forum, Thread, Bug web page, etc. :) I can also make a post about all of this, then I am sending you here, a one last time best regards of mine.