We'll need a bit more detail to help. There's general guidance in Using TalkTalk Mail
What is the email domain - the bit after the @ in the email address? Do you usually sign in to TalkTalk Mail or use an email client or email app. Any error messages?
If the email system has detected a weak password or a compromised email account, and changed the password or locked the account to help secure customer data, you may need help to recover access.
Password Reset details may have been set up for the email address so that an alternate email and or mobile number can receive the reset. Please do try the Reset your Password option. If there's an alternate shown that you recognise from the hints, and have access to, then please reset the password. If you can sign in to TalkTalk Mail then select the password reset to be sent to the account itself or, preferably, update Reset details via the main menu.
Or if you're a TalkTalk broadband customer or recent customer you can change your email password in MyAccount > My Services > Webmail - Manage Webmail, if the email is listed in one of the 5 email address slots.
Here's the advice article on managing your email in MyAccount.
If the self-help password change / recovery options aren't effective then I'll alert the TalkTalk Community team for you.
In the meantime, please update your Community Profile Personal Information (Click here) to include your name, current contact 'phone numbers and address with postcode (location) then scroll down and add the email address to Private notes and Save changes.
Hi peterh9, as Gondola says we need some more information in order to offer you the help you might need.