keybase Error: Error: no valid primary key self-signature

Hello,

when trying to provide my private key, the systems replies with:
keybase Error: Error: no valid primary key self-signature

https://keybase.io/prado/key.asc
## thank you

antonio

Start by examining the linked key.asc and reproducing the reported private-key import error with the Keybase client. Confirm the key's primary-key self-signature is the condition being rejected, and document a reproducible cause and resolution.

Written by the indexing model from the issue text.