Connect vpn

List of countries where the Firefox built-in VPN is available: Unable to find the built-in VPN in Firefox

No, it's not a matter of sanctions.

As of this afternoon, it displays a message stating that it is not supported in Iran. Given that the internet is subject to sanctions—necessitating the use of tools to bypass restrictions—why has this access been removed, and why has this issue arisen?

It was never available or offered in the region. There are no local endpoints for the service. (In other words — if you manually changed internal settings to connect "somewhere" despite that, you've put the load on some other market's infrastructure, which the service provider might have disliked, and made adjustments for that.)

So, nothing has been officially confirmed, right? But why were the service providers fine before, and now things have turned out this way?

You can potentially thank the "unofficial" VPN apps parasiting on the free offering, mostly coming from the regions where the service was not actually even rolled out. I'm not a lawyer so I haven't checked the Terms of Service, how enrolling into features normally unavailable fares in that matter, but this might be the answer to that. (Note: the exact same vendor providing the MASQUE network is the same as the one providing bot/abuse protections for Mozilla services, so it's not hard to see the connection between the two, as both are "under the same roof".)