Sounds like clematis wilt to me. I doubt that organic fungicide would cause your problem. If it is clematis wilt just cut it back and wait for it to grow out.

Josephine doesn't get clematis wilt. At least in my 12 years of growing mine I never saw it wilt, while a couple got shovel pruned because of that. It might still come back, keep your fingers crossed! Clematises are quite resilient. Good luck!
Grow

She is coming back, Yea!!
Thanks for your input.

Clematis can experience phytotoxic reactions when sprayed with certain chemicals during daylight hours. And organic fungicides DO contain chemicals, just natural rather than synthetic ones. This sounds exactly like what has happened with Josephine. Phytotoxicty, while a shock on the plant, is not fatal and it will recover quite rapidly with normal care after being cut back.

FWIW, Josephine is a type 2 clematis and most definitely can get clematis wilt - all early blooming LFH's are susceptible. Also, Josephine was only introduced in 2002 so hard to have been growing it for 12 years at this stage of the game :-)