Thanks to all for your replies and suggestions regarding my problem with the Tune in app (free and paid) on my Nexus 7 tablet. I have tried clearing the data, force stop, and uninstalling/reinstalling and am not able to connect with any stations. The screen says "opening" and after about a minute "could not connect to stream".
Yet I have no trouble opening stations on the IOS version on my iPod Touch.
Some of the stations that open almost immediately on my Touch but not at all on the N7 include San Diego radio stations like the following: Jazz 88 (88.3 FM), KPBS (89.5 FM), and 1090 AM (Sports XX). Distant stations like WETA (90.9) in Washington
DC and WBZ (1030 AM) in Boston also load quickly on my Touch but never connect on my N7.
I have looked at the settings and they seem the same on both devices. I have signed in to Tunein and that allows saving favorites on the Touch but doesn't help with connecting on the N7.
At this point I think I will use another radio app on the N7. Thanks again for all your efforts.