Could not connect to partner error

I've been a TeamViewer user for over 15 years but the last few days I cannot connect to either personal laptop. I keep getting the "Could not connect to partner" error

I'm using a free account and it's been working fine connecting via the TeamViewer android app but cannot connect now.

I've rebooted all devices just incase with no success. Does anyone have any ideas how to fix this?

Thank you in advance

Lee