chore(errors): review all errors in codebase

internal/provider/ipvanish/connection.go

@@ -1,23 +1,16 @@
 package ipvanish
 
 import (
-	"errors"
-
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/provider/utils"
 )
 
-var ErrProtocolUnsupported = errors.New("network protocol is not supported")
-
 func (i *Ipvanish) GetConnection(selection settings.ServerSelection) (
 	connection models.Connection, err error) {
 	const port = 443
 	const protocol = constants.UDP
-	if *selection.OpenVPN.TCP {
-		return connection, ErrProtocolUnsupported
-	}
 
 	servers, err := i.filterServers(selection)
 	if err != nil {