Item sold but the tracking number can't be added to the tracking details page

[nika1320nikolay]

I have sold an item with GSP.
I'm trying to add FedEx tracking number to the tracking information and after clicking on the "save" button the tracking information can't be saved, tried many times, its the first time something like that is happening, I have sold many items before.

would like to have some help here.

sorry for my English.