Problemas ao anexar docx

Front-end
#1

Estou com um problema na minha aplicação para anexar específicamente arquivos do office 2007, outros arquivos, anexam normalmente. Alguem já passou por um problema parecido antes?

Obrigado.

#2

Aqui vai uma lista das extensões e seus respectivos Mime Types.

Por exemplo, se antes .doc => application/msword, agora .docx => application/vnd.openxmlformats-officedocument.wordprocessingml.document

.docm,application/vnd.ms-word.document.macroEnabled.12
.docx,application/vnd.openxmlformats-officedocument.wordprocessingml.document
.dotm,application/vnd.ms-word.template.macroEnabled.12
.dotx,application/vnd.openxmlformats-officedocument.wordprocessingml.template
.potm,application/vnd.ms-powerpoint.template.macroEnabled.12
.potx,application/vnd.openxmlformats-officedocument.presentationml.template
.ppam,application/vnd.ms-powerpoint.addin.macroEnabled.12
.ppsm,application/vnd.ms-powerpoint.slideshow.macroEnabled.12
.ppsx,application/vnd.openxmlformats-officedocument.presentationml.slideshow
.pptm,application/vnd.ms-powerpoint.presentation.macroEnabled.12
.pptx,application/vnd.openxmlformats-officedocument.presentationml.presentation
.xlam,application/vnd.ms-excel.addin.macroEnabled.12
.xlsb,application/vnd.ms-excel.sheet.binary.macroEnabled.12
.xlsm,application/vnd.ms-excel.sheet.macroEnabled.12
.xlsx,application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
.xltm,application/vnd.ms-excel.template.macroEnabled.12
.xltx,application/vnd.openxmlformats-officedocument.spreadsheetml.template
#3