Today I found a portal owned by my faction that had a full house of 8 L1 resonators. I have a couple L2 resonators in my item inventory and wanted to deploy one. From the portal's main actions screen I selected Upgrade. From there I was shown a close up of the existing resonators that I could cycle through. Unfortunately, the Upgrade option on each of them was grayed out for me. Clicking on it only produce a text-over error:
No usable resonators
I checked my items list and there are still two L2 resonators in my inventory. What am I doing wrong? How can I deploy these resonators to the portal?
Best Answer
You cannot deploy resonators that are higher level than you, even if you have them in inventory. If this is the case, only way to do the upgrade is to first upgrade your access level (ie. level up ;) ).
If you had L2 resonators and are L2 or higher player level, then it is likely to be just a server glitch and retrying after a short time would have worked.
You can also get this message when you're already at max resonator limits. e.g. as an L5 player, you have 2 L5 res deployed and try to 'upgrade' an L4 on the portal - it will say 'no usable resonators', because you cannot deploy a 3rd one.