As much as we support Google's efforts to keep hackers and spammers away from our email accounts, it often leads to some inconvenience for the users. This of course is unfortunate, but often time required.
Recently Google rolled out a new system to improve their security. This did unfortunately create some issues for YippieMove in the sense that many of our users' received an 'invalid credentials'-errors when trying to create a transfer to or from Gmail (despite the fact that they entered the correct password).
We have been able to reproduce this issue, and here are the steps you need to take if you are affected by this.

If your login attempt with YippieMove failed (and you know you entered the right password), try logging into your Gmail account. If you see a notice like the one below, you are affected by this issue. If so, click the link that says 'Show details and preferences in the red warning-bar at the top.

When you get click on that link, you will be taken to the page that looks like the page below. Make sure it says 'cloudsigma.com' below 'prevented application sign-in' and that the timestamp matches when you tried to create the YippieMove transfer. If that is the case, click 'Yes'.

When you click 'Yes' above, you will be prompted to confirm the choice. Make sure to click 'Yes' here too.

Upon clicking 'Continue' on the page below, you have ten minutes to create the new YippieMove transfer. If you not create the transfer within ten minutes, the account will be locked down again.