Oh, that's funny. The only ISP that services my current domicile blocks sites all the time in the name of "safety," including several I need to access for my job. I have to use a VPN just to get things done. There's no appeal process or channel, either. Thankfully, I'm a month out from moving somewhere that has actual choice in providers, though I'll probably still use the VPN anyway.

Sounds like you have some kind of parental controls or safety filters enabled on your account. You can probably disable that in your account settings. I had an ISP years ago that blocked spam, malware, and phishing sites from Google's safe browsing list. Could just disable that feature in the account portal.

If you're on a typical US ISP, there is probably a way to avoid all filtering: pay for a business account rather than personal. Not saying it's fair or right, but it usually is an option