HashCat BruteForce Help usage

[tilershadowy]

I have a sha256hash with this value XCehCf3Awy

it has Upper case ,Lower Case and Numbers

is the best method for this hash -a 3 ( BF)?

and im trying to use it like this :

hashcat -m 1400 -a 3 test.hash ?a?a?a?a?a?a?a?a?a?a

But Im getting this error :

Integer overflow detected in keyspace of mask: ?a?a?a?a?a?a?a?a?a?a

what is the correct usage for option -a 3?

Your use case is correct, it's just that you are giving it a very large keyspace. I think ?a is about 95 characters or so, meaning you're feeding it a keyspace of 95^10, which is quite large.
Instead use -1 ?l?u?d ?1?1?1?1?1?1?1?1?1?1redactle
It will decrease the keyspace to 62^10. Still a lot, but maybe more manageable.

After I fixed it according to your instructions, it worked properly. Thank you.