The worker asked to create a waiting channel in a stopped state

I am a regular user of shinyapps.io. I recently got the following behavior:

1) gray screen + "disconnected from the server ... reboot" 2) reboot and get An error occurred ... The worker asked to create a standby channel in a stopped state.

Wait a while (1 min 3 min) not sure exactly) and it reboots normally. Disconnected from the server. I don't think I'm doing something radical different from earlier, but googling this error message only gives me one hit here: https://groups.google.com/forum/#!topic/shinyapps-users/AMROjcib8DA

I am unable to replicate the problem locally. I cannot find a set of clicks on a web page that repeat the error. I don't believe it is using very much memory - running locally memory.size (max = F) returns 76.26.

I am using R version 3.4.0. I have Windows 7 and I use a free account at shinyapps.io

Any help is greatly appreciated. Thank!