[Android Q&A, Help & Troubleshooting] MotoDefier:
I will be working on this as I just started getting a similar message but the problem with mine is not the fan, the dialog box I get says" the battery life-cycle limit reached. please contact after-sale support to change a new battery. projector will turn off in 5 minutes. this is ZTE using randsomware on their device to extort you out of more money to keep your device running. this is at the moment an unproven theory but is supported by the following information that has conflicting accounts given from different branches of ZTE USA support staff.

contacted ZTE USA support from live chat on the ZTE USA support site. The support assistant told me that the battery needed to be replace and that it would cost 150USD for me to ship it to the repair facility and have them change the battery, I asked if I could purchase the battery as I was fully capable of making the exchange myself since it is no longer under warranty. I was told that under no circumstances would ZTE make the battery available for purchase except through paying for them to replace it, I searched around and found an aftermarket battery for 30USD with the exact same specs and battery connector as the original. (ZTE does not make these batteries, they are Samsung cells as I found when I took the original out which had swollen so much I couldn't close the unit around it while I waited for my aftermarket battery to arrive so in a way cool points to ZTE for making sure your battery didn't explode after it had a fault) I purchased the aftermarket battery and was able to do the full teardown, battery replacement and rebuild in less than 10 minutes meaning they are charging over 250USD hourly for repairs when the techs that do these repairs make on average 12-14USD per hour.

after replacing the battery I powered up the device and the dialog and shutdown still happens. I reached out to ZTE USA on Twitter because it was a weekend and livechat was unavailable on the support page to request the reset code/software/jig that is used to reset the message and shutdown function and was told that no such thing exist, and was asked to send it in for repair if the following steps did not remove it, It was then detailed to me that all ZTE does at the repair facility when replacing a battery was to install the battery, do a master reset on the device and reflash the firmware. I downloaded the firmware from the link on the ZTE USA support site. because it was not labeled update.zip which is what the stock recovery requires to flash the firmware, I asked a support assistant through the live chat on the support site if the linked firmware was the signed zip since it will not flash an unsigned update.zip in the factory recovery environment, the support assistant came back with "unfortunately you will have to send it to us to have the firmware reflashed as ZTE will not allow support staff to send firmware or provide download links to official firmware and that the link on the support site was NOT the official firmware. The support assistant then quoted the same 150USD charge to flash the firmware and not replace the battery since I had already replaced it. I decided to try the flash anyway as if it was not a signed firmware file it would just fail to flash and I would still be in the same predicament. it flashed successfully (proof support staff is lying to get repair orders filled and sold)

I followed those steps, replace battery, master reset, reflash the firmware. power it up, the dialog and shutdown still persist.

what's interesting to me is if there is not a software/firmware reset code, why is there a root application in the google playstore that is capable of resetting this issue?

the developer of the app is charging around 30USD for a permanent reset, but you can use a temporary free reset to "make sure its going to work before you purchase the full reset"

this issue has affected so many people I have decided I will be rooting my device, to find this issue myself, I will then try to build a team of developers to help me create a custom recovery/ and up to date ROM as well as a custom bootloader (i'm not 100% sure but I've seen a few posts that say the bootloader can be unlocked) for this device that will remove ZTE's randsomware without getting rid of the protective features. PM me if you have any experience in development of custom TWRP builds, and Custom ROMS and would like to contribute to restoring the proper function of these devices for everyone that has one.