A guest says they uploaded a selfie but got no photos. What should I check first?

Work through the usual suspects in order. Is the album actually published? Draft albums show nothing to guests. Was the selfie a clear front-facing shot and not a HEIC/HEIF file — iPhone originals are the classic culprit. Is the guest accidentally blocked (check the album's blocked list)? Did they complete registration properly with the consent ticked? If all of that checks out and matches still fail, raise a technical support ticket with the album details — and have the guest try a fresh, well-lit selfie in the meantime.