Alena Yildiz from Germany shared her story ... "My close friend uninvited me to her wedding because she thought I looked too good in the dress she chose for me," immodestly adding, "Still took some fire pics in it though."

Now here's the thing ... it ain't the usual ugly bridesmaid's dress, so what gives? Yildiz opened up to Insider, saying she's being treated differently from the other bridesmaids ... "all of our other friends wore extravagant dresses as well, but she only had a problem with me."

We'd call it a humble brag, but the fact is ... she pulls off the look in spectacular fashion!

Yildiz claims the bride was honest and insecure, saying the dress was "too attention-grabbing." She thinks it's all the bride's screw-up ... if she thought the dress would be too sexy on any of the 6 bridesmaids, she should have chosen an uglier garment ... certainly not one with a thigh-high slit.

BTW ... the friendship between Lildiz and the bride is kaput ... "It made me feel like I had no value to her as a friend."