Anchor
InstructionFallbackNotFound
“Fallback functions are not supported”
No instruction matched the discriminator and the program has no fallback handler.
Common causes
- The client IDL is out of date and uses an old instruction name.
- You are calling the wrong program id.
How to fix it
- Regenerate the IDL (
anchor build) and update the client. - Verify the program id in the client matches the deployed program.