I updated to Mojave 10.14.3 last weekend at home. When I brought my MacBook Pro into the office Monday morning it showed it was connected to my office network, but there was no connection. I restarted the MacBook and it connected flawlessly. When I brought it home that night it said it was connected to my home network but it wasn't. Restarted and connected fine. Four days later it's still doing this every time I switch networks. Not a huge deal, but kind of a pain. Any suggestions?
I have the very same problem however it is not a WiFi problem at all as my WiFi was fine. Talked to 3 Apple support advisors before they connected me with a senior advisor. The problem was that when I upgraded to Mojave I somehow Encrypted the OS which can easily happen. Seems the Encrypted version affects BlueTooth, WiFi which interferes with internert access. The solution was to do a back-up in Time Machine, then totally wipe (erase) your hard drive then reinstall Mojave (no Encryption)---And when you get to the option to transfer files, skip it and let it load. Then test your WiFi internet then restore any files. Worked perfectly for me. Most of the 1st level support people do not know about this issue.