cannot upload attachments

every week for the past 2 years, when I post my ad, I have been able to click on the "manage attachments" option and upload my photos
This week, when I tried to upload my photos
, I got the message "upload of file failed"
have tried every day for 4 days----keep getting "upload of file failed"--
what do I do to be able to upload my photos in the "manage attachments" ?

I don't know too much about that but maybe either the attachments are too big or your attachment storage is full