What should I do? I only notice now that I had one message unread...of a biggest multinational company, asking for a interview in early November.

At this point, you have nothing to lose. Contact their Human Resources department, explain that you changed email addresses and did not get their message until now, and ask if an interview is still possible.

Write back and explain honestly that you have been employed, away from that email account, and have only just now realized that they had interest. (Don’t give too much detail.)

Follow up, by all means. Very large companies often take a long time to fill positions, and have a lot of positions to fill. Include an updated CV or resume (to show the current / recent employment), and absolutely provide current and monitored email and telephone contact information.

First of all, set up forwarding from the old inbox to the one you check regularly, so that this doesn’t happen again. This assumes that the old service provides this feature- some do not. If they don’t you might be able to get a third-party forwarding service set up; I have heard of such things but I don’t know how they work (or even how they can work) nor can I cite any specific ones to try.
Second, go ahead and contact the company, just as @CyanoticWasp and @marinelife say. There is no downside.