"umbracoDbDSN": "Server=WIN-A6AV861G7GP\\SQLEXPRESS;Catalog=databasename;User ID=Administrator;Password=Password1", "umbracoDbDSN_ProviderName": "Microsoft.Data.Sqlite" https://cdn.discordapp.com/attachments/1320579863752478720/1320580134436339722/Schermafbeelding_2024-12-23_om_03.33.18.png?ex=676a1d97&is=6768cc17&hm=65ceef3c6d1e77f8800b330bbf05a1efa1cd4d82205ec92921520c8fcb0d7dcb& https://cdn.discordapp.com/attachments/1320579863752478720/1320580134977146983/Schermafbeelding_2024-12-23_om_03.33.44.png?ex=676a1d97&is=6768cc17&hm=517cfda2e85f10982a9e06dc2f2654912337b68c0921d12134e8790dab7dc684&

The error comes from Microsoft libraries, not Umbraco. So is that even a valid connectionstring for Sqllite? 'Server' should be 'Data Source', right? You're using a full SQL server, so should the providername be changed?