Pro License user but error message says I need a license

I have bought a Pro License a few years ago and suddenly I was on a free Pro Trial License (not sure how that’s happened). The Trial has ended and it has overridden my paid for subscription and now I cannot receive or send any emails unless I purchase another license? Please rectify asap.

Go to Menu > Help > License and click on Activate, then paste in your license key.

If you have lost your key, you can have it resent to you from the Lost Activation Key page.

Thanks Gary! It worked!