Lost ability to change font color for text in existing document

When using Writer, in an existing document, I am now unable to change the colour of the text font. After making the change, the font still appears black… The exact same thing happened when I was using Open Office. I am using the LO Writer on a Mac.

Which version of LO and file format are you using? If you are using a non-native file format (e.g., DOC/DOCX) is the file being edited in (for example) Word in addition to Writer? How are you attempting to change the font colour? Via toolbar button of through the use of a style?