Both devices are capable of secure mail and encryption to TLS 1.2 so that's good. If those are the only devices connecting to the mailbox and they weren't set up for secure mail then IMAP access will have been withdrawn as a last resort action to stop the use of insecure connections.
I'll provide guides below so you have a check on the required settings and request full access is restored.
The Samsung mobile app - access will need to be restored by TalkTalk before the phone will authenticate a connection.
The incoming and outgoing server settings to use for all TalkTalk Consumer email domains are:
Incoming mail server: mail.talktalk.net
Port: 993 (for IMAP secure) 995 (for POP3 secure) so check the account type already setup - IMAP or POP3
Security type: SSL
Outgoing mail server: smtp.talktalk.net
Port: 587
Security type: TLS
Require authentication for sending mail: ON (switch to the right)
Prepare for TalkTalk Support - include in the Community Profile (not in these public posts):
Account holder name, TalkTalk home 'phone number (if not Data Only broadband)
Alternative mobile contact number. Full address with postcode (in the Location box)
Scroll down to Private notes to add the email address and customer account number
Check and Save changes
Select here: Update your profile
The TalkTalk Mail Support Hub is your go to resource for information, guides and Community support for TalkTalk Consumer home broadband and MailPlus subscribers.
Select here:
TalkTalk Mail Support
TalkTalk Mail help
Email settings and device setup guides for TalkTalk Mail
Setting up TalkTalk email on an Android device
