I see no particular issue with the google mail servers that are sending the emails to TalkTalk. There's a valid SPF file, a DMARC policy and DKIM signing so unless those emails have some undesirable content there would be no reason to block them unless multiple TalkTalk users have marked them as spam.
What is the bounceback error message, do you know? If TalkTalk are rejecting the emails there would usually be a bounceback error message. I very much doubt TalkTalk are blocking the Google mail servers as that would impact multiple sources of incoming mail.
Have you checked your own online mailbox to make sure there is no block on Google mail servers?
Select here: Sign in to TalkTalk Mail
Enter your full TalkTalk Mail email address and password, select Sign in.
Check the Inbox first and then check Spam and Trash folders for mail messages that may have been diverted from the Inbox. Bear in mind the spam and trash folders normally contain mail not older than 30 days.
Mail not reaching the Inbox could mean there's a Filter rule that's diverting, discarding or blocking mail.
- To check, select the Main Settings menu icon triple line icon top right on the blue header
(Mobile browser? use the desktop version)
- Select Settings from the top of the menu
- Select the inward facing arrowhead by Mail (or Email) in the left side panel
- Select Filter Rules
If there's no rule defined, that's perfect
- To delete a Filter rule including any Auto forward
select the Dustbin icon to the right of the rule
The icon background will turn red
- To confirm you really want to delete this Filter rule
Select the blue Delete button
If there is any Filter rule especially a Blocked Senders Filter rule then delete them all to make absolutely sure there's nothing affecting inbound mail reaching your Inbox.
Bear in mind that if you have any mail collection service or email software picking up mail using POP3 commands then that service or software may be downloading and deleting mail from the Inbox.
