I just went throught this, I discovered they moved it smart home vs devices like they had it before. I had mine set up with good morning/night and a few other routines like off 3am just in case one falls asleep watching TV. Everything still works like before just have re add it to routines via smart home now.
This happen to me overnight last night 10/14/2019 was working fine when we went to bed and this morning getting error message that she cannot connect to TV check network connection and power. But everything is working.
I have an Amazon Echo Dot 2nd Gen, and a Vizio smart TV, which have worked together very well for a year. I have previously been able to turn the TV on, off, adjust volume, change inputs, etc. However, in the past few months my Echo Dot started giving me the same error message as has been described above where it is having trouble connecting to device. I tried the soft reset and also reset the TV back to factory settings, but none of these methods resolved the issue. I finally found that my Vizio Smartcast skill in the Alexa app was disabled or even missing. I'm not sure if I accidentally removed it recently, or how that occurred, but I enabled the skill and had to relink the Alexa app with my 'myVizio' account and then the voice features through Alexa began working again.