The inability to read an e-book on a mobile phone was usually caused by the damage or loss of the e-book file. You can try the following methods to find and recover lost e-books: 1. Downloading and installing a reader such as a Kindle or readstar. Use this reader to open the e-book file to see if it can be opened normally. If this method does not solve the problem, you may need to download and install a new reader. 2. If the e-book file is stored on the phone, you can try to recover the file on the phone. Please make sure that you have backed up all the data in your phone so that you can restore it in case of any problems. If the phone does not have a built-in backup function, you can try to use a third-party backup tool to back up your data. 3 If the e-book file is stored in the cloud, you can try to see if the file can be restored on the cloud platform. Many cloud storage platforms provide file recovery capabilities such as Google Drive and Dropbox. Please make sure that you have backed up the data on the cloud platform so that you can recover it in case of any problems. If you still can't find the e-book file after trying the above methods, you may need to contact the phone manufacturer or the cloud platform's support team for help. In this case, you might have to pay a certain fee to get help.