two digital products links are not sent dont know why

Old digital products links are sent but not new ones which i added in last week and this week.
When customer purchases my video clips i complete orders manually after confirming payment. all old clips links are sent to customer but not the new two products link which i sent in last week and one yesterday.

if client purchases one old clip and one clip i added last week. he gets link for old clip but not for the one i added last week.
Please reply really urgent.

sorry there is an update its something strange. i have added one product today and its link is sent when i marked order as completed. have issue with only two products in my store which’s links are not being sent. i am using dropbox as my file hosting and have installed plugin WooCommerce Dropbox 1.1.1

all other links are being sent only two products have issue. have checked everything and its completely fine. no idea whats going on.