Webnovel.Forum

I guess it's somehow connected to Northern Lights buying licensing rights for some of the manhwa presented on the Webnovel (like Only I level up) as that would mean that Webnovel is no longer allowed to distribute those IP on the territory of Ukraine (that's also the reason why you can't buy digital manga on Amazon.jp as they don't have rights to sell it to you). That is in case Northern Lights own exclusive rights.
Maybe some other company bought exclusive licensing rights and filled a complain to Webnovel for stealing their profits, and we are soon to see light novel flooding the Ukrainian market.
Or Webnovel themselves just aren't buying rights for Ukraine anymore. Because, obviously, they could've just blocked certain novels from being available in Ukraine, but if the profits from this market were too low for them, they may have decided to just block it completely instead of trecking which novels they are allowed to distribute here.