I have uploaded my build to iTunes connect, and set up internal testing with TestFlight, but my testers are not receiving any invite emails, and my iTunes connect is acting odd. My build has a yellow warning sign next to it, i'm not sure why. Please tell me what I am doing wrong. I am pretty sure that it has something to do with my provisioning profile. I think the pictures below will be most helpful in terms of extra info.
Your third screen shot explains why:
To use TestFlight beta testing, build 1 must contain the correct beta entitlements.
You should follow the instructions in the FAQ link that the error message gave you.
Contrary to the other answer, you can beta test with internal users without review. For external beta testers, you do need a review, but it's less comprehensive than the one for the App Store and typically only takes a day or two.