1. There is something wrong with the signature photo itself: for example, the photo format is wrong, the photo pixel is not high, and so on. , resulting in the wrong signature when the phone opens excel, so it is necessary to re-create and upload the signed photos.
2. There are problems with the mobile phone software itself: the software version is too low, and the software has bugs. , you need to change other software to try.
3. There is something wrong with the hardware of the mobile phone: for example, the camera pixel of the mobile phone is low and the memory of the mobile phone is insufficient, so it is necessary to check the settings of the mobile phone and software.