I had this problem a year ago, it’s come back.
Some Smartthings devices in google home were offline so I unlinked google in Smartthings and then when I went to connect them again I keep getting an error message.
Depending on the device it says either ‘something went wrong. Try again later’, or ‘Can’t reach Smartthings’.
Hi, @Andrew_Bartlett
Have you reported this to Customer Support? They should be able to escalate the issue appropriately.
I have just now, thanks
Did you get a solution to this? I’m also facing the same issue. It’s been very frustrating. Tried for weeks now and still having the same issue. Keeps getting “Can’t reach Smartthings. Try again.”
Having the same issue, has this been escalated yet?
@nayelyz I logged this call and they sent me instructions on how to connect a device to SmartThings. Is there any way of connecting support outside of the App. The 1st line support don’t seem to understand the issue is with connecting SmartThings to Google Home
Hi, @Jeff_Gallagher
There’s an option to enter the SmartThings site, I believe.
What did they reply with that made you think they don’t understand the request?
They just send out a standard reply,
and then a load of random information on device compatibility, they mark it as answered an no way to reply.
Logged it again, this time they suggested a remote session, however they seemed to understand the issue now. And within an hour it back working
Edit 
and it’s Gone again added two devices neither appear in Google home, try to sync all devices and it cannot reach the SmartThings servers again
Try it again. Mine is back this evening
Report it to Customer Support
I have reported it using, Support, ‘send feedback’ in the wonderful Samsung Members App.
I found a fix, which was in Google Home, Settings, Works with Google, SmartThings, Check for new devices.
