The IRS only likes ASCII characters. ASCII stands for American Standard Code for Information Interchange. The first 128 characters are all the characters from your keyboard. The lower and upper case letters, digits and extra characters like !@#$% and so on. Examples of non-ascii characters are é, ö or ĉ and more. Anything with an accent or tilde are not characters that your keyboard can naturally generate.
Whether you file a Form 1095, 1099, 8027, 1042-S, 8966 or anything in between, the IRS will reject a file that has non-ascii characters. Some non-ascii characters are really hidden and very difficult to find. One way to find non-ascii character is by using Notepad++. In Notepad++, go to
Search | Find characters in range | Non-ASCII Characters (128-255)
Then step through the document to find each non-ascii character.
