Vaadin App on Azure Throws a Connection Drop Error or Create Instance Excep

Hello everyone,

We have recently migrated our alpha-version Vaadin App to the Azure cloud environment, binding it to a public IP address. In our series of alpha tests, either one of the four problems get cropped out, which I’d appreciate any input help of the following, randomly:

  1. Unable to create an instance of {0}. The constructor threw an exception (happens when a next request is issued)
  2. JDBC connection gets reset. (We are still using the C3P0 connection pool)
  3. 502 Application Gateway error
  4. A (never ending) message: Server connection lost, trying to reconnect.

Sometimes the resource consumption spikes up high that it needs to be rebooted.

Previously, this does not happen if this is deployed in a local physical server.

I am also not sure if the problem for #1 above is servlet-related just as discussed in this thread:, as it was written around 8.0; we are using 8.3.2. If that problem is entirely due to servlet, does it warrant a need to use Spring Framework’s servlet or a normal overriding of ServletBootstrapHandler.getServiceUrl(…) would suffice?

For #2, if this is caused by the connection pool, is switching to TomcatCP or HikariCP much advisable?
For #3 and #4, is there further need to adjust the networking rules, Tomcat or Azure settings?

Appreciate help as the input would be incorporated into the next major release of the app.

Thanks in advance!