Hi,
I hope, nothing would have been changed in the config. Can you please get the below information:
1: get sa
2: get sa id <id number of the dialup vpn from the previous command> , e.g. get sa id 1
3:debug flow basic for the working and for the non working stream?
https://kb.juniper.net/InfoCenter/index?page=content&id=KB12208&smlogin=true&actp=search
4: What client are you using?
Thanks,
Vikas