So, I have the portal key to a level 1 portal that I "own". I went about 10KM to a level 4 to link to it. When I go to create the link, I select the key and click create. It SAID link successful, but when I look at the map it doesn't show up. I tried this at another nearby portal and the same thing happens. The portal key isn't in my inventory anymore, but if I force close the game and relaunch it shows up again.
To clarify: I only have the portal key to the destination portal. The origin portal is level 4, the dest portal level 1. The resonators on both portals are at anywhere from 40% to 80%