From what I can tell, the official announcement threads pertaining to free weekends don't get much traffic so I wanted to post the issue in the general discussion as well.

https://forums.ubi.com/showthread.php/1933535-Free-Weekend-Thursday-September-20th?highlight=free+weekend
https://forums.ubi.com/showthread.php/2048521-Ghost-Recon-Wildlands-Free-Weekend-May-2-5
^See my replies.

Long story short, I was only able to play a greatly truncated segment of penultimate free weekend and wasn't able to participate in the latest one at all. The PS4 client seemed completely unaware of the fact that a free weekend was even happening and ate away at the free trial timer which is supposed to be for people playing the demo outside of the free weekend. When the timer was up, I was unable to play for the rest of the free weekend. Then, when I tried to play during this free weekend, I couldn't play at all. I received the same error message that my timed trial was up and that I should purchase the full game.

I think it would help the prospect of Ubisoft addressing the issue if other players could corroborate that they also could not play. Surely I'm not the only one. I'd imagine most free weekend players don't frequent these forums, and likely saw that they weren't able to play, got discouraged, and quietly gave up. Perhaps one of you tried to get your friends to play with you this weekend an encountered an issue?

It just seems odd that Ubisoft would go on a marketing blitz to advertise the free weekend and not have it function.