Yes, I thought you were in Belarus.
TBH I'm not sure, but it does seem possible that you may be being affected by country sanctions.
I have asked the staff here if they can clarify whether CCleaner is currently being affected by new EU sanctions on Belarus.
We are aware that CCleaner can get caught up in such sanctions, it has been before.
If so then there is not a lot CCleaner themselves can do about it, it's politics.
We'll have to wait for the staff's reply to be sure whether CCleaner is being affected or not.
Background:
The EU imposed new sanctions on Balarus at the end of June, but such things take time to put in place and may only now be affecting people.
https://www.consilium.europa.eu/en/press/press-releases/2021/06/24/eu-imposes-sanctions-on-belarusian-economy/
Although not specifically blocking internet access it does prohibit the supply 'directly or indirectly' of certain softwares that could be used by the military or by 'specified persons'.
That 'indirectly' can mean that it prohibits supply of those softwares to anyone in the sanctioned country.
(As you say, sanctions such as this are politics and affect lots more than those who they are aimed at).
What you can do:
As said above , if it is a sanction block, then you should still be able to run your existing CCleaner when not connected to the internet.
The cleaning functions will still work, but the other tools, and updates, may be blocked.
You may also be blocked from downloading new versions until the sanctions are lifted.