Topic on Project:Support desk

I'm writing an article on my wiki and for some reason, when I add the following sentence into my article, it just sends me back to my home page without saving. What's the problem?

The paragraph:

In the run up to the 2014 Scottish Independence Referendum, Tavish and his Orkney counterpart Liam McArthur put forward a motion to the Liberal Democrat conference to recognise the Islands having a "separate right to self-determination". Having been a career-long critic of Scottish Independence, Tavish campaigned for a No vote in the independence referendum. A majority of Shetlanders - 64% - agreed with Tavish and voted against Scottish Independence.

If I remove the " " then it works. Do I need to fix something in local settings?

Are the " " copy-pasted from another source, or were they typed directly by you?

See Manual:Errors and symptoms#Attempting to save an edit gives you a 403 Forbidden error, or you get redirected to the main page