Cannot upload new theme - receiving file size 1500kb error

Maybe Jack K. would be willing to handle this, because he has all the log-in and FTP info.

I've uploaded and installed the Avada theme with no problem on several stand-alone sites. Now I'm trying to upload it via the Network Admin dashboard, because that seems to be the correct option for uploading on a multisite. (I installed the Holder theme with no problem, but it's only 1123kb.)

As you can see from the attached composite image, I am getting an error message. The Avada theme is only 7590kb, so this shouldn't be happening. I haven't changed any file limitations in any .php files. Is that what I need to do to allow installs of themes that are 8 to 10mb in size?

I did search the forum first, but couldn't find the answer.
Thanks for any assistance