Hi @D2021 and welcome here!
In general, these kind of pages present a high(er) risk for any user accesing. If OTP detected that, than it is for your own safety not to access it. It is , of course, you decision.
Many of the mining pools and/ or mining software (e.g. even Nicehash, which is a very known one) are regarded suspicios by all the respectable AV vendors. We are trying to provide the safest solutions for the mass customer base and cannot risk them being exposed.
Cheers,
Mike