Do you have the time set to automatic? If not, do so.
If it's set to automatic, do you live somewhere where the time is 15 minutes off from an exact number of hours different than GMT (just search GMT in a web browser to see the GMT time.) If it is, your carrier isn't aware of your country's (or part of the country's) time difference. (Automatic sets the time based on the tower you're connected to.) You could also be right at the border of a time zone, connected to a tower on the other side of the border, and the time on that side is 15 minutes ahead of yours. (Come countries do strange things.)
If none of the above apply, contact (or go into) your carrier. They can actually generate any time they want at any particular tower - it's supposed to be the GPS time (plus or minus the time where the tower is from GMT, of course), but some of them use the time from something else, and that can be wrong. (GPS time can be off by nanoseconds - that's how GPS works - time difference between satellites, but it shouldn't be worse than 1 part in 10^8 or 1 part in 10^9, which we can't even notice if we're looking for it. 1 in 10^8 is 10 nanoseconds.)
07-11-2020 04:09 PM
