After Elon Musk’s Twitter tirade on an overly simplified solution to the Ukraine-Russia war, his company Starlink is now being questioned for its timely outage to Ukraine’s Internet service.

Ukrainian government officials anonymously spoke with Financial Times and revealed that Starlink had been offline multiple times in various instances when Ukraine was pushing toward Russia. The officials said this created a “catastrophic” loss of communication between troops.

Ukraine’s advantage over Russia has been its advanced communication lines and its support from satellites and drones in locating enemies. However, after Starlink stepped in to “donate” satellite internet access to Ukrainian troops.

V.S. Subrahmanian, a professor of computer science at Northwestern University, told Newsweek that Starlink stepped in after Russia “basically took out all of Ukraine’s military communications.”

“I think the fact that Starlink communications have been disrupted in the key theaters of battle right now, mainly the territories Ukraine is trying to take back…The fact that that’s gone is definitely placing a dent in Ukraine’s plans,” Subrahmanian added.

Subrahmanian added that there is little chance this was done by the Russians. Since Starlink has a high-precision ability, the connection was likely cut off on regions previously occupied by the Russians. So, when the Ukrainians came to liberate these regions, they could not connect to Starlink immediately.

Musk also took to Twitter to debunk FT’s claims, saying none of these happened and that this “donation” is costing him $80 million “and will exceed $100 by end of year.”