I've received an error that my CSV Template has illegal characters (non UTF-8 Format). How can I fix it?

Normally, this error is due to non-processable characters found in your CSV Template. When processing your CSV Template, we do not allow any illegal characters for security reasons. Most of the time, the illegal characters can be found in your FIRST NAME or LAST NAME columns. For example, O’Brian needs to be replaced with OBrian.