Livemail sounds like Fasthosts, who have stated that they have had a problem following an "improvement" to their email service - note the date.
Interestingly I had to change the port numbers recently on an Outlook 2019 client on the office PC in a sports club I belong to due (I suspect) to this.
https://www.fasthosts-status.co.uk/
Mail Infrastructure Update: Client Settings
Identified - Following recent improvements to our backend mail systems, you may need to update your incoming and outgoing server settings to ensure connectivity.
If updating the settings does not resolve the issue, please take a backup of your mail content (export a backup from the mail client), then remove and re-add the mailbox on your device. You can find the correct settings in our help guide here:
Set up email on your device Jan 21, 2026 - 13:32 GMT