Typically, the polarity of the analog cable does not matter, at least in the US it usually does not matter.
You can try a couple of things.
1. Verify that you do not have voice mail on the analog lines so that they have a stutter dial tone. The Tenors cannot detect this.
2. If this only happens on 1 or 2 analog ports, try swapping lines/ports around to verify if the ports have gone bad on the Tenor.
3. If you are using a GSM unit, make sure that everything is properly grounded.