It is a bit weird, I tried to save your plot with tiff() and dev.off() and it seems to work. I did not modify anything about your plot (t), so if you run your code and then run my code below you should find the plot (named test1.tiff) in your working directory. Maybe the issue was related to the dimensions of the image you were creating? 1100x600 seems to work fine to me (unless I'm missing something)

tiff(paste0(getwd(), "/test1.tiff"), height = 600, width = 1100)

t

dev.off()