207: Unmatched right cross

The left cross +- is used together with the right cross -+ to cross out text. You used the right cross without a corresponding left cross within the same block.

Solution

Add the missing left cross within the same block to cross out text. If you want to use a combination of hyphen and plus sign literally instead, prepend a backslash: \-+

Here is a minus-or-plus sign to copy and paste, in case you are looking for one: