iPhone "SIM card invalid" error after restoring via DFU - what to do?

Question

iPhone

Hello everyone
Problems with iPhone 6 Refurbished
After I restored it from DFU, this error pops up during activation. Previously, it worked well, I inserted a SIM card when I bought it, activated it without problems.
Yesterday, the iPhone suddenly turned off and stopped loading (infinite apple). I tried to restore it via DFU, but for some reason the progress bar on the iPhone did not go (the bar simply did not fill up). Then I disconnected, brought it out - entered it into DFU, tried again and restored it a second time, but now this error.
What to do? Has anyone dealt with this?

Answer 1

hmm .. Usually such a problem if the device was previously locked