It seems the phone won't allow my laptop to connect: the phone says the hotspot is active, I've checked that the password etc. is correct but the laptop says the problem lies with the "router". Also, I've put the sim into another phone (an old Blackberry) and the connection is fine so the problem must be with the J4/Pie. I should add that I've tried Samsung Technical Support but found that it is not operating - the "Live Chat" is down and my attempt to send an email was blocked. Is there anything more I can tell you?
I have the same issue with the J4. Seems like the problem is the Android 9 - Pie. If you really need to use the hotspot, i might suggest that you set the hotspot to an Open network (no password) and then set it as Allowed devices only (so that only you can access your hotspot). Weird that you can connect to your hotspot with an Open network but you can't if it's password protected (WPA2 PSK).
Yes I'm having the same problem, hotspot worked fine until the update and now it only works if I remove the password. Have it set to allowed devices only but I would really love if Samsung fixed their mess!
Just an update for this. I downloaded and updated the latest version for Android pie. It just worked after the update. Looks like Samsung did something with this. The update was just around last week. Please do try to update yours as well. Got mine working again. Thanks!