User talk:2A04:B2C2:180A:D100:5925:7E20:EC92:B56

Deadly Class parameter error
Hello 2A04:B2C2. Please note that your recent edit caused a in the list of books, since you introduced an invalid ISBN. (The error shows up in red print, if you view the article). This is caused by using an ISBNT template with an empty value for the ISBN. If you can't find a valid ISBN for this forthcoming book I suggest you undo this addition, to fix the problem. It is already somewhat questionable to announce forthcoming books in Wikipedia, per WP:CRYSTAL. Thank you, EdJohnston (talk) 16:15, 4 October 2019 (UTC)