I got a call on a Wednesday and we scheduled an on-site interview for Friday. The manager was very pleasant and informative; the interview was a very positive experience and lasted for about 3 hours. A week later, I received a phone call and a HR representative said that they would like to extend the offer. I try and follow up the next two working days only to get a call back on the third day when they expressed their inability to give me the offer because I was on STEM OPT Visa. I tried to explain that I am willing to work even without an H1B sponsorship but I didn't get any response thereafter. I had mentioned my Visa status in the online application itself. I just wish they wouldn't have gotten my hopes up and made me go through the entire ordeal before leaving me in the dark.