Hello Soizic
If you have not reset your Flickr account's password in the last 2 months, then you will need to reset it before you can login to your Flickr account. Once you have reset your Flickr password, you will need to reauthorize Photo Mechanic to access your Flickr account, using the new password. Click the Authorize button in the Flickr uploader dialog. A new web browser window will open for your Flickr login. Enter your email address and the new password and then click the authorize button. You should see a successful login confirmation message next. Close that window and now you will be back to the Flickr uploader dialog. Click the OK, l'LL AUTHORIZE IT button to complete the Flickr setup. I am attaching my Flickr setup pdf from PM 469. The setup steps are the same for PM v5.
regards,
--Bob