Error on launching session

Hello, I get the following error in my map when launching a session:

We encountered an error preparing your project. Error: errors.com.epicgames.content-service.cook-failure, An error occurred while communicating with the game servers (Content (re)cook error errors.com.epicgames.cookplugin.cookfailure.
JOB_ID=0a1384cf-ac9e-4cf4-a474-3e736802edee)., CookJobId:0a1384cf-ac9e-4cf4-a474-3e736802edee
LogFortExposedAssetSubsystem: Warning: UpdateLocalCollection - Could not find ValkyrieSentryManifest.json
LogWindows: Error: appError called: Assertion failed: r == METIS_OK [File:D:\build\++Fortnite\Sync\Engine\Source\Developer\NaniteBuilder\Private\GraphPartitioner.cpp] [Line: 181] 
Call to METIS_PartGraphRecursive() failed - error code: -3, Graph->Num: 13042344

LogThreadingWindows: Error: Runnable thread Background Worker #4 crashed.
  • This happens only on this map
  • There are no devices in the map
  • I have not written any verse code
  • There are no materials with special functions
  • I did import static meshes that worked fine until now

I merged some meshes, which ended up being more than 200MB large.
Removing those solved the problem.