Not enough credits
The button says what the render needs and what you have; here is what to do about the gap.
Pick a cheaper version: the line under the composer lists what your balance covers — one take, the shortest clip on this engine, an image instead.
Top up with a pack or take a plan from Billing; credits land immediately and the button updates.
In a team, check whether an admin set you a monthly ceiling: the refusal says so, and the Members tab shows it.
A 402 from the API means the same thing; nothing was charged.
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Erzähl uns, was passiert ist – wir antworten innerhalb eines Werktags.