Warhammer: Vermintide 2 is great, of course, but that does not mean it's not tackling a few problems of its own, like the dreaded Backend Error. Error 1342 is a particularly heinous problem, as it has a tendency to cause progress loss practically rendering your playtime void!
Vermintide 2 Error 1342 is, according to the developers, Fatshark, a server-side issue, and seemingly stems from the server's inability to resolve a connection with the client. Since all player data is stored server-side, this makes it so that in-mission progress gets reset and effectively nullified in some cases.
What is Vermintide 2 Backend Error 1342?
"Our service provider is having issues in their data centre. This is leading to outages across all our platforms. We'll monitor and continue to relay information as it is provided. Apologies for the trouble in the mean time." said the developers, speaking on the issue of 1342.
Just last year, the increased number of Error 1342 reports were signed off as related to a substantial influx of players, who servers had a hard time keeping up with. Now, what this means is that the issue can not be fixed on your end, and seeing as how it keeps popping up from time to time, it's likely related to downtime or maintenance on the servers themselves.
The only way for you to minimise the odds of Backend error 1342 popping up is to maintain a stable Internet connection, and hope Fatshark's servers manage to do the same. Rest assured, when it pops up, they're likely to be working on a fix.