diff --git a/common/keydb/keydb.go b/common/keydb/keydb.go
index b9fa884e2..26d3a33b7 100644
--- a/common/keydb/keydb.go
+++ b/common/keydb/keydb.go
@@ -16,7 +16,6 @@ package keydb
 
 import (
 	"context"
-	"errors"
 	"net/url"
 
 	"github.com/matrix-org/dendrite/common/keydb/postgres"
@@ -39,6 +38,8 @@ func NewDatabase(dataSourceName string) (Database, error) {
 	case "postgres":
 		return postgres.NewDatabase(dataSourceName)
 	default:
-		return nil, errors.New("unknown schema")
+		// if the scheme doesn't match, fall back to postgres in case the config has
+		// postgres key=value connection strings
+		return postgres.NewDatabase(dataSourceName)
 	}
 }
diff --git a/federationsender/storage/storage.go b/federationsender/storage/storage.go
index 8cffdbf1a..a632449e5 100644
--- a/federationsender/storage/storage.go
+++ b/federationsender/storage/storage.go
@@ -16,7 +16,6 @@ package storage
 
 import (
 	"context"
-	"errors"
 	"net/url"
 
 	"github.com/matrix-org/dendrite/common"
@@ -40,6 +39,8 @@ func NewDatabase(dataSourceName string) (Database, error) {
 	case "postgres":
 		return postgres.NewDatabase(dataSourceName)
 	default:
-		return nil, errors.New("unknown schema")
+		// if the scheme doesn't match, fall back to postgres in case the config has
+		// postgres key=value connection strings
+		return postgres.NewDatabase(dataSourceName)
 	}
 }
diff --git a/mediaapi/storage/storage.go b/mediaapi/storage/storage.go
index 0f39c1d0c..3e9e4ef6e 100644
--- a/mediaapi/storage/storage.go
+++ b/mediaapi/storage/storage.go
@@ -16,7 +16,6 @@ package storage
 
 import (
 	"context"
-	"errors"
 	"net/url"
 
 	"github.com/matrix-org/dendrite/mediaapi/storage/postgres"
@@ -42,6 +41,8 @@ func Open(dataSourceName string) (Database, error) {
 	case "postgres":
 		return postgres.Open(dataSourceName)
 	default:
-		return nil, errors.New("unknown schema")
+		// if the scheme doesn't match, fall back to postgres in case the config has
+		// postgres key=value connection strings
+		return postgres.Open(dataSourceName)
 	}
 }
diff --git a/publicroomsapi/storage/storage.go b/publicroomsapi/storage/storage.go
index a6a39d523..7018507e9 100644
--- a/publicroomsapi/storage/storage.go
+++ b/publicroomsapi/storage/storage.go
@@ -16,7 +16,6 @@ package storage
 
 import (
 	"context"
-	"errors"
 	"net/url"
 
 	"github.com/matrix-org/dendrite/common"
@@ -45,6 +44,8 @@ func NewPublicRoomsServerDatabase(dataSourceName string) (Database, error) {
 	case "postgres":
 		return postgres.NewPublicRoomsServerDatabase(dataSourceName)
 	default:
-		return nil, errors.New("unknown schema")
+		// if the scheme doesn't match, fall back to postgres in case the config has
+		// postgres key=value connection strings
+		return postgres.NewPublicRoomsServerDatabase(dataSourceName)
 	}
 }
diff --git a/roomserver/storage/storage.go b/roomserver/storage/storage.go
index 325d96e99..8ad2dde84 100644
--- a/roomserver/storage/storage.go
+++ b/roomserver/storage/storage.go
@@ -16,7 +16,6 @@ package storage
 
 import (
 	"context"
-	"errors"
 	"net/url"
 
 	"github.com/matrix-org/dendrite/roomserver/api"
@@ -67,6 +66,8 @@ func Open(dataSourceName string) (Database, error) {
 	case "postgres":
 		return postgres.Open(dataSourceName)
 	default:
-		return nil, errors.New("unknown schema")
+		// if the scheme doesn't match, fall back to postgres in case the config has
+		// postgres key=value connection strings
+		return postgres.Open(dataSourceName)
 	}
 }
diff --git a/syncapi/storage/storage.go b/syncapi/storage/storage.go
index eedb42f0e..de9a6bef9 100644
--- a/syncapi/storage/storage.go
+++ b/syncapi/storage/storage.go
@@ -16,7 +16,6 @@ package storage
 
 import (
 	"context"
-	"errors"
 	"net/url"
 	"time"
 
@@ -58,6 +57,8 @@ func NewSyncServerDatasource(dataSourceName string) (Database, error) {
 	case "postgres":
 		return postgres.NewSyncServerDatasource(dataSourceName)
 	default:
-		return nil, errors.New("unknown schema")
+		// if the scheme doesn't match, fall back to postgres in case the config has
+		// postgres key=value connection strings
+		return postgres.NewSyncServerDatasource(dataSourceName)
 	}
 }