A message keeps flashing up 231 fatal error. Can you let me know what I need to do. 0116 240 3430 Dorothy

231 fatal error is telling you that the data from the chip on the toner cartridge is invalid or cannot be read.

This may happen for one of the following reasons:

1)The printer is unable to read the data on toner chip because of toner dust or dirt inside the printer.
Solution: Clean the printer inside, clean toner slot and drum.. See:Clean your laser printer.

2)Either the toner is not an original cartridge, it is refurbished or refilled, or the chip on the toner cartridge is defective.
Solution: replace the toner, or replace the Chip on toner cartridge.

3)The toner sensor in your OKI is defective.
Solution: Call the support number listed on the printer manual to arrange repair.