Seems that Mac and Android phones are not too friendly, however there are some ways that may help you transfer files to each other.
1. Transfer using Android File Transfer
A simple app which can be downloaded from Google Play, if you find it hard to use just search and try others as the Store is full of free good apps.
Step 2: Launch the installer and drag the Android File Transfer icon into the Applications folder before launching the software.
Step 3: Plug your device into the computer using a USB Data cable and keep the screen unlocked in the process. Now you can browse/edit/move/delete files/folders on your device.
2. Transfer using DropBox
Dropbox is a usual file hosting service, the only thing is that you can get it on your computer/device like a simple folder what make’s it easier to manage. So if you have access to other cloud services you may try this method using the Cloud you use.
Step 3: Run the app and login with your account details
Step 4: Now, tap the three dots in the top-right corner of the app and select Upload here to choose files or folders you wish to upload to Dropbox. Other way to upload on Dropbox is to press and hold a file/folder till a menu pops up, click Share and select Dropbox. When you’ll be connected to the internet, your files will upload on Cloud.