Create a time series collection from two timeseries with different TimeInfo Vector

I created two timeseries objects using

ts=timeseries(Data,Time);

Time is datenumber. Both timeseries have different start and end time but the second one is a subset of the first. Both the timeseries have the following TimeInfo:

Common Properties:
          Units: 'seconds'
         Format: ''
      StartDate: ''

But when I try to combine them in a Timeseriescollection using:

tsc=tscollection(ts1);
tsc=addts(tsc,ts2);

, I am getting the following error:

Error using tscollection/addts>localCheckTS (line 142)
The time vector of the time series you are adding must match the tscollection time
vector.

Error in tscollection/addts (line 80)
        localCheckTS(h,data);

Can anybody help me how to solve this problem.