When I check the player.log in "C:\Users\<username>\AppData\LocalLow\Tactical Adventures\Solasta" the following error message shows up:

Exception caught when reading user location file C:\Program Files (x86)\Steam\steamapps\workshop\content\1096530\2866570835\Shadows over Brightreach.json: System.NullReferenceException: Object reference not set to an instance of an object
at UserItem.PostLoadJson (System.Boolean& someContentRemoved, System.Boolean& someContentFixed, System.Collections.Generic.List`1[T] removedContent) [0x00033] in <8fd4463fb73749ffbab8fa19e37a5ed5>:0
at UserCampaign.PostLoadJson (System.Boolean& someContentRemoved, System.Boolean& someContentFixed, System.Collections.Generic.List`1[T] removedContent) [0x0009e] in <8fd4463fb73749ffbab8fa19e37a5ed5>:0
at UserCampaignPoolManager.ReadCampaignFromDisk (System.String filename, System.Boolean& someContentRemoved, System.Boolean fromGamingPlatform, System.Boolean fromExternalSource, System.Collections.Generic.List`1[T] removedContent) [0x00079] in <8fd4463fb73749ffbab8fa19e37a5ed5>:0
(Filename: C:\buildslave\unity\build\Runtime/Export/Debug/Debug.bindings.h Line: 39)

Unexpected timestamp values detected. This can occur in H.264 videos not encoded with the baseline profile. Timestamps will be skewed to correct the playback for C:/Program Files (x86)/Steam/steamapps/common/Slasta_COTM/Solasta_Data/StreamingAssets/BackgroundMovie.MP4
(Filename: Line: 0)

I've tried downloading the campaign several times. Even deleting the folder. But nothing helps. The file itself is to large to find out where it is incorrect.