The 'Real Housewives' star was just dropped by a brand with whom she had an endorsement deal -- Positive Beverage, a natural energy and vitamins drink she'd been repping of lately. This isn't a coincidence -- PB canned her as a direct result of her behavior regarding 'rona.

They write, "Our core values of wellness, community, diversity and inclusion should be reflected by our brand and anyone associated with it," adding ... "it has become clear over the past few months that Kelly's controversial views and opinions have distracted from our primary objectives, so effective today, we are no longer affiliated with Kelly Dodd-Leventhal."

Positive Beverage goes on to say while it welcomes a mix of people with differing views on things, there's gotta be an underlying layer of respect ... and they feel Kelly's lost that, and thus -- she's lost them too. It's a big deal ... Kelly was a big deal for them, appearing in several sponsored posts.

We're sure she was collecting a nice check from them. You'd think she'd be pissed, but not so ... Kelly had a quick, snappy response to the news.

She writes, "I'm glad I could help put Positive Beverage on the map and wish them well. I’m also really excited about my next venture in the beauty industry, which is my real passion. Stay tuned!" Sounds like there's no love lost on her end either.

Of course, this comes directly on the heels of Kelly going out and recording herself dining with friends at an OC restaurant ... where a bunch of them jokingly called themselves "super spreaders" and mocked mask-wearing and the virus as well.

She's made other comments about the pandemic that were eyebrow-raising ... some for which she's apologized. KD kept at it though ... and this mighta been the last straw.