After DVLS upgrade from 4.7.1 to 6.0.0 Windows Authentication stopped working

Hi,

I have a problem after an upgrade with SSO in datasources, it works with manual signin but not with Use Windows Authentication:

Devolutions.RemoteDesktopManager.Business.TryGoOfflineException: DVLS server is not responding.

The remote server returned an error: (500) Internal Server Error.
at Devolutions.RemoteDesktopManager.Business.DataSources.RDMSConnectionDataSource.cb6f90699089bd1c9688221883b0c338f(String c18973cea236a9feff75c32ca7d1697d5, String ceb81d1ee93f91e0bc57f34876c263863, Boolean c8c947c51eb176e7175409fd081e947ab, Boolean c2de1417c23cd0676ca16f3b418d16455, Boolean cd1019342f38d18a4083300b0c0b48efb)
at Devolutions.RemoteDesktopManager.Business.DataSources.RDMSConnectionDataSource.c88b8bc6e236931f324b713404e90b15d(Boolean c5d807049ab3ae30aad5318fa57dc6159, String& c18973cea236a9feff75c32ca7d1697d5, String& ceb81d1ee93f91e0bc57f34876c263863, Boolean c88d1c88a1983c4218837515ad03a99d0)
at Devolutions.RemoteDesktopManager.Business.DataSources.RDMSConnectionDataSource.Login(Boolean useCredentials)
at Devolutions.RemoteDesktopManager.Business.DataSources.RDMSWebApiClient.get_c3e2a9eaefc85e07772d691a26117253e()
at Devolutions.RemoteDesktopManager.Business.DataSources.RDMSWebApiClient.ce18a34186459a94774b0658f116cce91.c49e0e32005a95753415224597668b218()
at Devolutions.RemoteDesktopManager.Business.DataSources.RDMSWebApiClient.c5f4f6c72c053c0cd60a62abeeaa43fdf[cb75a0a5d15a1ad8b8a8a5e57cca214a3](c31561c0d54939abd223ac7c0cf30e7e6`1 c6cc9ab02b2ea9ccd42c7c0497677bcc2, ExecuteActionLogMode c92f46156e371279a4f61cd5822be5fee)
at Devolutions.RemoteDesktopManager.Business.DataSources.RDMSWebApiClient.GetData(String proxyConnectionCacheID, Byte[] version, String repositoryID)
at Devolutions.RemoteDesktopManager.Business.DataSources.RDMSConnectionDataSource.GetDataSourceSettings()
at Devolutions.RemoteDesktopManager.Managers.ConnectionManager.c29fbd34504079a3525ca4c390d5d4074(BaseConnectionDataSource c7f28727fc7a5daa94ba08f688b2a5781)
at Devolutions.RemoteDesktopManager.Managers.ConnectionManager.ca4799bebd8b706f34eea94a778843b55(BaseConnectionDataSource c7f28727fc7a5daa94ba08f688b2a5781, Boolean cfe205b02d73750f8fd14d199343fe545)
at Devolutions.RemoteDesktopManager.Managers.ConnectionManager.LoadConnections(BaseConnectionDataSource dataSource)


Removed/renistalled IIS Windows Auth feature, removed/enabled in DVLS. Checking SPN as we speak...