Server error: could not save one or more files. Please try again later

Server error: could not save one or more files. Please try again later this error come i was build app

Please check your network connection.

That may happen when you try to upload an supported file type also. Many times I have tried to upload .JPG file but I get the same error so if you are uploading an image convert it to .PNG first and convert audio to .MP3 for easier uploading.

Hello Fan Club

It could actually be the Server being very busy at that point in time but the error message is concerned with files and that often means the media files you have in your Project. Do you have any large image files for example? Via software on your PC, they should be reduced to or near to the finished size required by the App. If they they have no transparency, save them as 24 bit Colour, if they are drawings, save them as 16 bit colour.
https://www.professorcad.co.uk/appinventortips#TipsImages