Hello @Syed Ubedullah ,
It seems 2 got failed and the last one went through . Basically when you do copy using storage explorer, it internally runs azcopy command.
You can check the azcopy logs by clicking on the link "Go To AzCopy Log File" - It will have a text file which will show you the detailed error message why the copy is failing.
You can also try running the same AZCOPY command by extracting the exact syntax from the link "Copy AzCop Command To Clipboard" , before that you have to install AzCopy utility.
https://video2.skills-academy.com/en-us/azure/storage/common/storage-use-azcopy-v10
Regards,
Shiva.