I have problems with my greenhouse container grown (from seed) cucumbers. The plants sort of shriveled up when transplanted from the seed tray and while not dead are very sick looking, mottled crisp leaves and very slow growth. I had this trouble last year as well so this year tried using growbags but the problem has recurred. A plant I bought from a garden centre has thrived, healthy leaves and lots of flowers but the fruit are growing to about 1 inch and stopping there.
The one that is growing but not making fruit is proably growing too vigorously. Cucumber is not pollinated, so that is not the problem. Reduce watering to see if that reduces vigour and induces cropping.
Resume balanced watering when some fruit begins to form.