once hanged up, squid does not re-dial

Andy Weisel, Kempten. Need info / help. Have configured a Linux 6.4 machine as internet-router with squid. First dial works well. But once ISDN has hanged-up after app. 1 minute, when i want to actualize or open any URL similar to the recenet one, no re-dial appears. I get error "network/server may be down" from squid on my router machine. When i open any strange URL or yet unknown URL, squid / or ISDN re-dials correctly, and i can surf on... Who can help?? Thanks a lot Andy Weisel andy.weisel@allgaeu.org