The ADL has a good rundown on their website:
Ironically, some white supremacists themselves soon also participated in such trolling tactics, lending an actual credence to those who labeled the trolling gesture as racist in nature. By 2019, at least some white supremacists seem to have abandoned the ironic or satiric intent behind the original trolling campaign and used the symbol as a sincere expression of white supremacy, such as when Australian white supremacist Brenton Tarrant flashed the symbol during a March 2019 courtroom appearance soon after his arrest for allegedly murdering 50 people in a shooting spree at mosques in Christchurch, New Zealand.
The overwhelming usage of the “okay” hand gesture today is still its traditional purpose as a gesture signifying assent or approval. As a result, someone who uses the symbol cannot be assumed to be using the symbol in either a trolling or, especially, white supremacist context unless other contextual evidence exists to support the contention. Since 2017, many people have been falsely accused of being racist or white supremacist for using the “okay” gesture in its traditional and innocuous sense.
. . .
Because of the traditional meaning of the “okay” hand gesture, as well as other usages unrelated to white supremacy, particular care must be taken not to jump to conclusions about the intent behind someone who has used the gesture.