[Solved] Chromecast 2 - permanently loses connection with the network, reset does not hel

Hello
I have a big and repeating problem with Chromecast. Unfortunately, I did not find a similar event in googlu.
I have been a Chromecast 2 user since January 2018. The installation went smoothly. HDMI on TV and charger from 1000mAh phone. After downloading the update, it launched itself without any problems. First for a month on the Play internet, then from February on Netia. I was very pleased with the device and recommended it even successfully to several people. Effortless operation ended in mid-May. One day it stopped being visible to devices on the network, ie the mirroring button disappeared. I checked the internet, everything OK. I wanted to set it up again via the Google Home app and unfortunately I could not find my network, although other networks of neighbors were visible. I decided to restore the factory settings and reconfigure everything.
After restoring the factory settings (pressing and holding the button on the Chromeca for a few seconds until it stops flashing), the problem is the same when reconfiguring. I still can not see my wifi network. I checked with colleagues on 2 other networks. Their network was searched and it was possible to configure it without any problems. It worked.
Not wanting to run the complaint procedure with a clear conscience of my and the seller who checked himself, I exchanged the device for a new one in a friendly store. Once again, the installation, updates, my network visible and everything OK. I thought it was the previous device.

Unfortunately, it worked without problems this time only for 3 weeks. The same action: it was no longer visible to devices on the network, ie the mirroring button disappeared. Trying to connect to another network - no problem. An attempt to manually enter my network without a result. Restart just like before and nothing like that. He can not see my network. This time, at the instigation of a friend, I also restored the WiFi router to factory settings and changed the network name and password. Still nothing.

Is there any other method to restore factory settings? The one I was doing is not quite full factory reset. It seems to me that it only removes some of the settings. I say so because after reboot it does not download the update that I downloaded after buying and first launch. Is it possible to completely erase devices in some way?

One more thing, with both Chromecast devices, after restoring them to the factory condition in a phone connected to my wifi network, Chromecast is visible under the name "room.b". I gave the name "room" at installation every time. After the failure Chromecast added ".b" to the name and so showed up in available networks on the device connected to my wifi network. There was no visible network such as with a brand new device.
In the case of installation in a friend and connection of the phone to his network Chromecast among the available networks appeared under the name such as brand new.

Exchange to another device as you can see does not solve the problem in the long run.
Anyone have any idea how to solve the problem? How to perform a full reset?

Thanks in advance for your help

I have the same problem. Did you manage to fix it somehow?

Unfortunately, it failed.
All attempts without results.
So far I have included an additional router from the internet provider. In another network it works, but it is not a solution.

I found the solution on one of the English-language sites, in my case it helped to enter the password manually, and the network with the added "b" sign, ie the chromecast itself, which is trying to connect to the mobile device. I can not find this page quickly, but it can help:
https://support.google.com/chromecast/forum/AAAAt7PFQG4TusXGQkLGTc/?hl=en

You have to change the WiFi transmission channels in the router. Set to the car and it will be ok

In my net router, the channels were set to auto. After rebooting the router and changing the network name and channel selection, the Chromecast auto can not see the network with the changed name.
For now, he uses the old solution, that is, through an additional old router connected with a cable to the netia. For now, it's been over a month without problems

I was helped by changing the channel on the router that I had manually set to 13. When Chromecast was re-configured, a message appeared that my device was not for my country and not all Wi-Fi networks would be visible. Try not to use channels that are not allowed in the US, i.e. 12 and 13 if you have a device intended for a market other than European. By the way, it's strange that on the first day Chromecast worked on the 13th channel and there was no problem. Maybe in the meantime an update is coming up, which "regulates" causing problems and losing the memorized Wi-Fi.