My McBook air will not load the current update

Try it from here, it's on a different server.

Download macOS Mojave 10.14.6 Combo Update

The Combo is a fuller install than the regular delta upgrade.

If instead you are looking for one of the Security Updates let me know.

You're welcome. No, I think it was just a one-off.

If you do you can always try downloading from here:

Apple - Support - Downloads

Which update are you trying to use?

OK, let us know.