Can my DNA results be wrong?

I am a female, who was adopted at birth.

I had been searching for my birthmother and found her through a 2nd cousin match on Ancestry, but she passed away in 2010. I was able to locate her brother, who was there for my birth. None of her family knew who my birth father was.

I finally got a 1st cousin match, in May of this year. He didn’t match with any of my bio mom’s family, so I figured he had to be on my birth father’s side. I messaged my 1st cousin, who is male. My 1st cousin told me his father, only had one brother, so we thought it had to be him. I sent him a letter in June and two weeks later, he called me. He said that he was dating his, now, wife, at the time, and she did not know about his affair. He said he remembered having a one night stand with my birth mother, the exact time-frame I would have been conceived.

He told his wife, who was less than thrilled, but is okay now, and his two grown children, and all was well. We were convinced, I was his daughter. We have been talking weekly, and have been forming a really close relationship. He decided to schedule a visit to come meet me in person, but before he came, I told him I’d like do a DNA test with him through Ancestry, just to make 100% sure, so I had it sent to him and he sent his test to Ancestry.

Since we were almost certain I was his daughter, (although it was against my better judgement. He was so anxious to meet me,) our visit was this weekend, even though the test results weren’t in yet. We thought we had another 1-3 weeks before the results were in. Last night, as I was about to take him back to the hotel, I was going to read my exchange with his nephew, my 1st cousin match, back when I first discovered our initial match on Ancestry.

I had a notification that I had a new DNA match. HE was the new match. I started reading the results, but it says “Close Family” match, not “Parent” match. I finally read them out loud to him and my husband. As I read the results to him, we all became heartbroken and crushed.

How could this be?

I am absolutely baffled!!! It’s showing he and I share 1,762 centimorgans shared across 48 DNA segments. Is he really my Uncle? My 1st cousin match, who is his nephew, is showing we share 1205 centimorgans shared across 40 DNA segments. My first cousin match and I put our raw DNA on GEDmatch, and it shows 1.8 generation. There are NO other brothers. Also, who I thought was my birth father, remembers being with my birth mother, around the time of my conception.

Could the test be wrong?

I am so upset.