Did you change anything with the wiring? This is a switch loop, so just connecting all the blacks together and all the whites together is not the correct thing to do.

It looks like there is one white wire that is marked as black and attached to all the other blacks. There should be a black wire that is in the same cable as that white one. Remove the black wire that is for the fixture from the wire nut and attach it to the black wire that is paired with the remarked white one.

So you'll have 3 wire nuts, not 2.

(1) All the plain white wires together.

(2) The remarked white and the two blacks that are paired with the plain white

(3) The black from the fixture with the black that is paired with the remarked white.

In case you're wondering 'why' it works this way. The remarked white takes the constant power to the switch and the black in the same cable brings the switched power back to the light.

Right now you have constant power connected to the light and constant power travelling on both wires to the switch. Flipping the switch on and off just connects the two constant power wires together and does nothing.

Wow! That did it! Thank you very much I really appreciate you taking the time to explain it! Thanks again!

Glad to have helped.

In the future, I'd suggest taking a picture of the wiring before pulling it apart so that you know how to put it back together again.