How do i fix my CR01 dyson washing machine?

I have a Dyson CR01 washing machine and it keeps saying close outer door even though the outer door is closed. I have turned the washing machine off then on again then quickly pressed temp then soil type which came up with the diagnostic mode 67F6F2F255V205. I then turned it off and on again and the diagnostic mode had disappeared and it appeared the washing machine had gone back to normal, however when i then pressed start it again said to close outer door. Could somebody please help me as i cannot afford an engineer and have been without a washing machine now for three weeks! Any answers would be much appreciated.