What does this error mean? I get a bunch of these...

2017-07-17 13:55:45 :We currently only support 50 second at a time due to physical memory limitations

2017-07-17 13:55:45 :We currently only support 50 second at a time due to physical memory limitations

2017-07-17 13:55:45 :We currently only support 50 second at a time due to physical memory limitations