I have an iPad Pro 11 and am unable to open 'secure' files as I keep getting the message that 'This file cannot open as it may not be secure or corrupted.' I received a very important message this morning from my teachers pension, but it won't open... any ideas please?
I hope you're doing good.
Per my understanding, this is a feature limitation; you cannot access(edit or use any tools) the encrypted files on the Acrobat reader mobile application. So, if you want to use and edit any encrypted file, you can only access it through the Acrobat desktop application.
I hope this helps.
Would you mind trying to open the document using Document Cloud Storage?
You would first want to upload the file to the cloud and then try opening it online directly. If it still does not open, there might be certain restrictions on the document which prevent it from opening on the mobile version.
Also, please check the same file with Acrobat on the desktop version.