I have combined pdf's to make 1 file. It has 277 pages and 266mb.
I save it which is fine but when i open up the folder i saved in ie. downloads...it isn't there.
I have tried saving it to adobe cloud also but it fails right at the end of completion
Hope you are doing well. Sorry for your experience with Acrobat Reader Mobile.
Have you checked for available storage space on your device? The error could be because of the storage quota getting exhaused.
You can check for available space from here: https://acrobat.adobe.com/link/home/
Also, while you do so, you can try uploading the file from the online portal directly and check if it uploads there.
Please let us know if this helps.