Have been having issues with WiFi connectivity ever since Marshmallow update on my Note 5. Issue is not specific to any one wifi connection - happens both at home and at work. I have forgotten and reconnected to networks, and have reset all network connections on the phone. I have to manually forget home network each time it connects when I get home each evening, and reconnect. Same thing when I get to work. Any way to get around this without having to constantly go into setting. If I walk out of wifi coverage at work, and then come back to my desk multiple times a day, it gets annoying.
Smart switch doesn't get your wifi issue resolved, it just uses the cell network for data when wifi is not available. The issue is that wifi is not stable with the MM update. If you can connect to a 5G network you may have better luck keeping a Wifi connection. If you have a 5G router it may let you name the 2.4 and 5G networks separately. This has helped greatly for me while awaiting the sure to come update to resolve this and other MM issues on Note5.
I've been having similar issues with my Note 5 since the update. I'm 12 days away from the start of a new billing cycle and I've used almost 90% of my data because it keeps kicking me off WiFi, get constant error messages about network connection and can't get half my apps to work (especially Facebook). After going to Verizon and having them replace my SIM card, I finally bit the bullet and factory reset my phone. Why am I paying nearly $700 for a phone that now doesn't function properly? I think Verizon should credit us some data, at minimum, and someone needs to find a fix soon!