Bigpond mail not working

As per questions previously asked (from other people) but not answered when I search here, i have on device my Mac OS running Big Sur has stopped being able to receive or send mail on 2 separate bigpond accounts, one a .com one a .net.au. The mail accounts still work on all other devices and webmail. Error for week has been timed out on port 993, but during trouble shooting today (finally had time) has changed to unable to verify account name or password. the Port error was coming up despite being on 'auto configure' and toggling between auto and manual settings made no difference until about 4th toggle it shifted to the name/password error. I have tried following a few online methods eg delete .offlinecache file (can't find such a thing), deleting keychain, deleting the whole account to re-add it - but now I can't even re-add it because it won't verify the name/password. Any suggestions, this seems to trip people up regularly per online but I haven't found a reliable 2022-dated answer that works! thanks.