Hello
I changed my home WiFi password and have lost connectivity to all 11 outdoor and 6 indoor V4 cams! None will restart but are showing 3-4 bars of reception. Am I looking at resetting every cam? 
The V3 cams have a setting on the app under Device Info to change networks, I don’t see it on my V4 cams.
If you have all V4 cams you will probably need to set them up again.
I found that after updating the first cam with the new PW all cameras updated. BUT THEY WOULD NOT CONNECT UNLESS I DID THE ENTIRE SETUP minus adding the updated PW. So lame.
There should be a shortcut to allow all or selectable cams on the same network to connect! Even though the PW was updated (internal to each cam), no cam would connect unless the full setup was completed. 
Did you update the password on all the cams before changing it on your router? If not, then the cams have no connectivity and no way to get the new password (without going through setup again).
I would have cheated. I would have made a Guest Network on the 2.4 band with the same SSID and old password for the cams and put everything else on the primary 5.0 and 2.4 networks.
!? I don’t know of a a way to manually update a password, or passwords, using the WYZE app! Is there a way? These are all V4 cams. If there is a way I stand chagrined and corrected…inclusive of more knowledgeable.
Thinking about it, if the cams were manually changed (?)…they all lose their connectivity. Are they capable of re establishing their connection once the router password is changed?
That’s a fine idea. However I’ve found no way to establish individual control of the devices sequestering them to connect to a specific network. Are the cams smart enough to just arbitrarily search for a new network of the same frequency and password once the primary router password is changed? I see I am perfectly capable of creating a guest network/password, but truly, how will the cams behave once connectivity is lost due to change?
As I mentioned, after the initial setup of the very first of 18 cams, all cams after that produced the new password without my intervention but still needed to be forced into re establishing a connection. So I digress, how are the cams going to reconnect by themselves? Are they that capable?
Some models of cam in the latest app have a change password feature where you put in the new password, then I believe reboot the cam after you’ve turned on your new router. I haven’t tried it so I don’t know the exact process. Not sure if both networks have to be online at the same time for a period or not.
I have my cams on my IOT network which nobody ever gets the password for and is isolated and firewalled off, so rarely feel the need to change the password. I think what @Antonius was suggesting was to just create a guest network with the old credentials and the cams would connect to that without having to update them. Obviously that’s a matter of personal preference and organization, but it isn’t a bad idea to have IOT stuff isolated off.
There is probably some documentation on the new password change feature of the app and how it works, but realistically the only way it could work is by sending the new info to the cam, then upon reboot it uses that. But it would require it to be done before you change your network or password, otherwise the cam is offline and can’t get that new info without the old push the button and set up process.