[SOLVED] The client lacks sufficient authorization :: The key authorization file from the server did not match this challenge

I don't understand how it's possible to create the order with one account and the content of the validation file with another account. But I use my own-written Letsencrypt - client. So I know the format of the file content - token, dot and the hash value.

The first part of your content is correct, only the second part is wrong.