504 Gateway Time-out

I have a Shiny app deployed the first time in 2017. I recently noticed the interactive map was not working properly so I updated the packages and deployed it again. I don't get any errors during deployment, and I can see it as "running" in Shinyapps.io, but I get a "504 Gateway Time-out" message when deploying and it just does not load (stays in "Please wait").

I couldn't find an answer anywhere. I've been trying for about 2 weeks. I made sure the files are not larger than 5MB and the overall size of the upload is below 20 MB.

Any help will be greatly appreciated!

have you checked the apps logs ?
I would use rsconnect::showLogs() with streaming=TRUE, in my console and then use my browser to go to the shinyapp to see what streams in

Thank you!
I seem to have found the problem, although haven't been able to solve it yet.

When I deploy it the Deploy display reads:
"Application successfully deployed to https://aquaticbushmeat.shinyapps.io/wildmeat/
Deployment completed: ..."

However, the logs in shinyapps.io indicate there might be a problem connecting to dropbox (rdrop2 package). The app needs to access a file there, and though there's an URL I should use to allow access, the local host refuses to connect, likely due to my antivirus.

Thanks again.