I just made my first sale today as well and also no label has generated. I checked my email, inbox and spam folders, searched everywhere on app on my phone and desktop computer and still nothing. I sent a message to request help and this was the auto reply:

Thanks for reaching out to us!

This is an automatic message. We hope it'll help.  

Your buyer has paid for the item, and you can now download the shipping label that you should use to send the package.

Once you press "Get shipping label" on the conversation screen with the buyer, a pre-paid label (i.e. a pdf document) will be generated on the conversations screen and also sent to your email.

⚠️The shipping label is created within one business day. If the buyer bought the item on Friday, you may not receive it until Monday. We are sorry, but we won't be able to speed the process up. Also, don't forget that you'll only be able to receive the label once the payment is fully processed.

Download the label from the app or your email, and print it out.

Stick the label onto your package and drop it off at your mailbox, nearest post office, or call USPS and order a pick up from home free of charge.

Here are some tips that might be helpful:

If you are having trouble receiving your label, check the Spam Folder in your email.

If you've shipped your item, and the tracking hasn't appeared, please keep in mind that it can take up to 24–48 hours for the tracking to update sometimes, so please don't wait until the last day to ship your package.

If you have shipped your item using a different shipping method or purchased your own shipping label, please reply to this message with your proof of shipping. We'll take it from there!

If you cannot send this item, and you have to cancel the order, just tap the "i" button in the top right-hand corner and select "Cancel order". Next, you should select the reason why you want this order to be canceled.

If you still need help with your order, please reply to this message, and we'll be happy to help.

Regards, Team Vinted