Self Assessment error message.

All I am trying to do is explain why I have no student loan, which was paid in full, No matter how many words I type, 1 or 10, I get the same error message, saying I can only use alpha, numeric and various characters. Please can someone advise why the words 'Loan repaid in full.' causes this error to show? I can't see what I am doing wrong? arrggh!! Thanks in advance.

Hi Michael Peters,
If your student loan has been fully repaid then once you submit the tax return HMRC will receive the details from the Student Loans Company and the calculation will be updated accordingly.
You do not need to enter details confirming loan repaid in full. 
Thank you.