I have the same problem, I use the following workaround
loadpath = # path to where plots should be stored
animation = Animation(loadpath,String[])
for i=1:n
p = plot(x,u_sol[i,:])
frame( animation, p )
end
name_of_gif = # name of file.gif
run(`ffmpeg -framerate 15 -i $loadpath"%06d.png" $name_of_gif`) # run this in the REPL, it will hang indefinetly, if the gif already exists
when you already go this road I would recommend to use a better format for the video like for example .mp4
with
run(`ffmpeg -framerate 15 -i $loadpath"%06d.png" -vcodec libx264 -crf 25 $name_ending_in_mp4`)