I have reset my iPhone

If your iPhone can't be activated or an alert says the activation server is unavailable [or cannot be reached], or the SIM card is unsupported, read this support article to learn what to do. "If you can't activate your iPhone [or iPad]" - click here --> If you can't activate your iPhone or iPad (Wi-Fi + Cellular) - Apple Support

- Note the special link at the end of the document for contacting Apple if there are still problems.

There have been a flurry of posts reporting this issue in the last half hour or so. There may be a problem on the back end. I’d give it some time, then try it again.