The founder of Rebel Media, a well-known conservative website operating out of Canada, says a technology company gave him 24-hours notice before seizing the domain.

Millions of people tuned in for Rebel Media’s YouTube channel over the past two years, but many fans were cut off from the main website Monday. Self-styled “Rebel Commander” Ezra Levant said the domain — TheRebel.media — was abruptly terminated for roughly half of his global audience.

“If this was a political censorship decision, it is terrifying — like a phone company telling you it is cancelling your phone number on 24 hours notice because it doesn’t like your conversations,” Mr. Levant told Reuters.

Mr. Levant declined to identify the technology company by name, but the development comes just days after he fired a star reporter for attending recent protests in Charlottesville, Virginia, and for agreeing to speak on a neo-Nazi podcast hosted by the Daily Stormer.

“It was just too far, and we said goodbye,” Mr. Levant said in a YouTube video uploaded Aug. 17. “Tough week, but we’re going to get back to work now.”

The Daily Stormer was recently cut off from its domain by Google and GoDaddy Inc. The website came under increased scrutiny after 32-year-old Heather Heyer was struck by a vehicle and killed Aug. 12 in Charlottesville.

Police arrested 20-year-old suspect James Alex Fields after he accelerated his car into a crowd of bystanders.