If you are using Blogger (blogspot.com)
Error parsing XML, line 1205, column 91: The reference to entity "u" must end with the ';' delimiter.
I listed 2 ways to fix the problem. The first way is, replace the 5 special characters with their entities' name manually- which will take time if you get some long codes.
That's why I provide the above tool- to do the replacement automatically.
The 5 special characters:
' need to be replaced with '
" need to be replaced with "
& need to be replaced with &
< need to be replaced with <
> need to be replaced with >
Wikipedia reference here.