Why this street label is not visible even with zoom?
It has 'name' in it...
It looks like the road is too short for the text to fit on, or it's too curvy. Check here for a similar solved question. A solution could be to either abbreviate the label, or simplifying the line might help.
EDIT: if you don't want to change the road then you could use rule-based labelling and create a new rule solely for that single label:
"name" = 'R. da Fonte do touro'
For that particular label I'd suggest setting the placement as below the line, offset by a slight distance. You could then also reduce font size to fit better along the line. Repeat or add other labels with similar issues.