@Andy Do you mean when flashing?
If so, you need to use a chromium based browser and be sure the T1000 is in DFU mode by quickly connecting and disconnecting the magnetic cable twice. (Although you may be able to enter DFU mode via the web flasher at this point though I haven't tried).
There is an example of manually entering DFU mode here.
https://wiki.seeedstudio.com/sensecap_t1000_e/#device-stuck-in-boot-loop