on 16-10-2018 10:25 AM
Without knowing what browser you're using or how its set up and what tracking / ad-blockers you're using, a diagnosis of what exact setup changes you need to make is not exactly easy.
But try the easy route first. Use a different browser, default settings, no cookie blockers and tell me if that proves you can set the TalkTalk preferences in your MyAccount and then not get the nag / reminder screen.
on 16-10-2018 10:06 AM
To update TalkTalk preferences you need to log in to your MyAccount using the normal MyAccount login email address as username and the MyAccount password.
If the TalkTalk Preferences nag screen keeps appearing every time you wish to login to webmail then it's because the browser you're using is not retaining cookies that store the TalkTalk preferences update.
The browser needs to be set to accept cookies and retain them. Private Browsing mode or the use of Ad-Blocker software or add-ons will block those cookies so if you don't want the nag page to appear just set the browser / ad-blocker / tracking blocker to accept and retain TalkTalk cookies so that once you've updated your TalkTalk preferences via your MyAccount you don't get nagged about that in future.
Try a different browser with default settings to prove that the issue you're seeing is related to the setup of your existing browser and or add-ons.