Avast Premium not recognising a new subscription

I resubscribed to Avast Premium Security a few days ago, wit ha few weeks left on my current subscription. I applied my serial number to the account using the app, but I’m still getting nagging messages that my subscription is due to expire soon.

How do I solve this?

When I enter my subscription key, it updates to tell me I have a year of protection, but when I close the menu, and reopen it, it reverts to 18 days.

click on instalation and at bottom of page click on activation issues then support https://support.avast.com/en-ww/index#pc

I uninstalled avast, then reinstalled it, and that seems to have done the trick. My account through the app says I have the years subscription applied.