Altitude always a negetive number

[jgroom]

We have this running on several blackberries but the Altitude always shows a negative number. We are not talking about a few feet below sea level ours usually show in the negetive 1000 plus range. Is this normal or is there a setting somewhere so we can correct this somehow.
Thanks

[ATSupport]

Please see: https://forums.accutracking.com/viewtopic.php?f=4&t=421