Question: Unable to update app: Error posting to URL: <https://appengine.google.com/api/appversion/create?app_id=ethereal-zodiac-803&version=1&>
409 Conflict
Another transaction by user suganya.karthik is already in progress for app: s~ethereal-zodiac-803, version: 1. That user can undo the transaction with "appcfg rollback".

See the deployment console for more details
Unable to update app: Error posting to URL: <https://appengine.google.com/api/appversion/create?app_id=ethereal-zodiac-803&version=1&>
409 Conflict
Another transaction by user suganya.karthik is already in progress for app: s~ethereal-zodiac-803, version: 1. That user can undo the transaction with "appcfg rollback".

Answer: 
If you are using maven, you can use [rollback](https://cloud.google.com/appengine/docs/java/tools/maven#app_engine_maven_plugin_goals) goal:

```
mvn appengine:rollback

```
Google App Engine Config Rollback command helped in Resolving the issue.

```
$ appcfg.sh rollback <war location>

```

The above command will prompt for a code. For this code, it will give you a weblink. Go to the link, get the passcode and enter it at the prompt.

For Full command see below (will help you to find appcfg.sh location)

```
$ /home/myuser/.m2/repository/com/google/appengine/appengine-java-sdk/1.9.27/appengine-java-sdk/appengine-java-sdk-1.9.27/bin/appcfg.sh rollback /home/myuser/workspace/MyProject/war/

```