Gatefan: could have been a browser hijacking attempt or someone trying to hack Telstra users.
So far,none of those has been tracked down to an ad on here,but there's always a first time for everything.
If you run malwarebytes or a similar programme,it will pick up anything your normal security missed if this happens again.
Can you give me a link or two to thread pages where you've had this happen,and the number of the error code if possible?
If you need anything restored or sent to you,and the posts weren't eaten by the forum or your phone browser glitches,that won't be a problem.