Application has stopped working because new access_token can no longer be generated

What was changed in Zoom by the end of March, 2024 what broke generation of new access_token using:

  • grant_type=refresh_token
    Tried to create new app from scratch and from my point o view this procedure " Step 2: Request access token" (OAuth for user authorized apps) completely doesn’t work - I’m constantly getting:
    “reason”: “Invalid client_id or client_secret”,
    “error”: “invalid_client”
    The app was created about three months ago and had been working smoothly till 29th of March 2024. Once again: what was changed in Zoom? I haven’t found any related information in the “releases change log” - Announcements.