I have a lime tree that I purchased about 5 years ago. It's been in a pot, mostly kept indoors except some short periods of time in spring/fall. I live in Reno NV so the winters are real and summers are dry and windy- not great for the lime tree. I've also had issues with scale bugs but they don't seem to harm the tree (I spray with soapy water and hat controls them enough)

The tree blooms like crazy in December/January and sometimes has a second bloom in early summer, however the tree has never produced real fruit. The blossoms fall off a few days after they open and for the last 2 years I've been monitoring the flowers: they look normal but they have NO POLLEN. I even took a hand lens to it to make sure it wasn't just my eyes. The photos attached are from this week. Clearly the plant is relatively happy, but why wouldn't the stamens have pollen on them?