Can't add a tracking number for an item I sold

[spiraldesignz]

I sold an item and shipped it yesterday with USPS, paid extra to get the tracking number but now eBay won't allow me to add it.  Does anyone know why?  I can click on add tracking but the drop down menu for the carrier doesn't work and the button to add it remains grey & won't work.  I can type in the info but it won't send.

[eburtonlab]

Other users are having problems uploading tracking using the website, but apparently the eBay app still works for that.

More here:

https://community.ebay.com/t5/Shipping/Can-t-add-tracking-number/m-p/34217726/highlight/true#M466810