Strava upload don’t work?

Hello everybody. 

I have downloaded a GpX file from cycle travel and want to upload it to Strava but every time I try,  it says - “time information is missing from the file” - is there a way to work around this error? 

I have checked the help section of Strava and it says files with that error message are not compatible with the Strava application. I’m on the free tier of Strava. 

Thanks in advance. 
SS.