Why is my Galaxy J3 Eclipse not compatible?
Because Visible has not tested it for compatibility. That said it well may be compatible. Order a SIM saying the phone is an iPhone 11 and carrier none. Ignore the eSIM and order a physical SIM
Hate to step in on this but that phone is from 2017 and you may run into issues of it not working even if you bypass the compatibility checker to get a SIM.