I have received a definitive answer from iFastNet about this issue. And I’m sorry to say: this is an intentional block, and it will not be lifted.
I’m not sure what you’re doing on Cloudflare Workers, but another person reporting this issue stated it was to be able to access Telegram’s APIs, which we have blocked deliberately.
And that’s precisely the reason we’re blocking access to Cloudflare’s workers now: it’s primarily being used to bypass the Telegram API stuff to send spam and for other abuse.
If you were using Cloudflare Workers for something else, then I’m sorry that you’ve fallen a victim to this. We don’t like having to apply these kinds of measures but free hosting attracts abuse, and we sometimes need to take drastic action to stop it, which may come at the expense of legitimate use cases.