Thanks,
I had the same problem when a secondary email account was moved to Telstra Mail. Could get to emails on my Android device but not PC.
After a few fruitless searches for Telstra Mail settings and so forth, got onto Telstra tech help, found it was my anti virus but got no further with tech help.
Not going to run a windows box on telstra without a good anti virus / internet security package running.
More searches for Telstra mail settings got the same info about settings for email client, not Telstra mail via browser.
Was being told that Telstra Platinum care would allow me to pay for Telstra to fix the problem they created.
Thankfully I searched for Kaspersky settings for Telstra mail and found this in crowd support before I was sent to Platinum care.
In Kaspersky, More Tools, privacy protection, settings, categories and exclusions, exclusions, add email - telstra - com.
Pity this wasn't passed to Telstra tech support yet, would save them a lot of time. Will let Tech help know next time I talk to them.
I can now see my emails using Firefox, Opera or Chrome, so won't have to make alternate arrangements before main email is moved to Telstra Mail.
Again thanks for the help