African country’s one mistake in first auction? (6,5)
I believe the answer is:
sierra leone
'african country's' is the definition.
(Sierra Leone is an example)
'one mistake in first auction?' is the wordplay.
I cannot really understand how this works, but
an anagram of 'one' is 'eon' which is within the answer.
'mistake' could be 'err' (synonyms) and 'err' is located in the answer.
'first' could be 'i' (I in Roman numerals eg Elizabeth I) and 'i' is located in the answer.
'auction?' could be 'sale' (I've seen this in other clues) and 'sale' is present in the remaining letters.
This accounts for all the letters.
This explanation may well be incorrect...
(Other definitions for sierra leone that I've seen before include "West African country, capital Freetown" , "West African nation" , "W. African republic" .)