This problem is typically caused by the number of images being added to the website and can be fixed by following the instructions below.

• Go to "Extras" > "Optimize all Images".
• Click "Optimize" to confirm.

Alternatively, you can optimize individual images by right-clicking them and selecting "Optimize Photo". 

The optimization feature performs three important tasks:

• Removing parts of images which are invisible
• Reducing the resolution of images to 96 dpi 
• Converting PNG and bitmap images to JPEG files at 75% quality

The optimization procedure makes the image files significantly smaller in order to save storage space.

If the project is still too large after the images have been optimized, you can get around the issue by splitting the project up into multiple subprojects:

• Copy the project as many times as needed. For example, let's say you have a project called "My_Homepage". Copy it three times and name the copies "My_Homepage_Part1", "My_Homepage_Part2" and "My_Homepage_Part3".
• Then, delete the pages you don't need in each part. For example, open "My_Homepage_Part1" and delete the pages you want parts 2 and 3 to contain. Then save "My_Homepage_Part1". Open "My_Homepage_Part2" and delete the pages you want parts 1 and 3 to contain. Then save "My_Homepage_Part2". Open "My_Homepage_Part3", delete the pages you want parts 1 and 2 to contain, and save it. 
• Export all the subprojects to the folder containing your original project. When you do this, rename the exported files to the name of the first page in each subproject. For example, rename the "My_Homepage_Part2" file to the name of the first page  in that subproject and rename "My_Homepage_Part3" to the name of its first  page.
• After renaming the subproject files, upload them one after another.

Your project now no longer links to internal pages within the project itself    (since the project is actually three different projects); instead, the project links to page names. These pages must be kept in the same folder in order for the correct references to be generated during upload and so the right information can be generated within the overall project.