What does the same device max count setting do?
The device max count to set a number of file to be sent for example if you set it to 500 and you have 1000 file only 500 files will be sent and the campaign will not send any file but the other campaign will continue sending the same example if you have 2 files and set maximum sent to 500 the number of sent will reach 500 and stop if you choose 0 the campaign will send without upper limit
