This is a recurring pro-Kremlin disinformation narrative about the elections in Ukraine.
As reported by StopFake, Ukrainians living in the Russian Federation or in the occupied territories of Donbas were not denied the right to vote.
According to Ukrainian civic network OPORA, an election watchdog, voting stations were in fact opened not far from the frontlines in the Donetsk and Luhansk regions. In the Donetsk region, there are 12 electoral districts (for an estimated 1.4 million voters), while in the Luhansk region, there are 6 districts (for an estimated 522,000 voters).
According to data provided by the Central Election Commission, residents of occupied Donbas and internally-displaced persons were also taking part in the election process.