My WiFi module can't find any kind of APs

[mvtdesign]

Hi, I have made 3 ESP8266 module, Then I flashed the modules with AT command, the latest revision, and now all of my modules aren't able to find APs.

The first one, worked well, but after a while, baud rate of the module increased to 250000 bps during boot (I had done a lot of tests to find the baudrate), and I couldn't execute any kind of AT commands on it (or at least I couldn't find the right baud rate).

The second one worked well, but after a while, the module was not able to find access point. even when I set the module as an AP, I can't see the SSID of the module on my phone or laptop. I can execute any kind of AT commands without any kind of error, but I cant find even the closest APs.

And the Third one worked only just once and then, it was like the second one and I couldn't find APs with the module. When I execute "AT+CWLAP\r\n" the response is "AT+CWLAP\r\nOK".

Also I have tried to flash modules a lot, I can upload AT command firmware without any error on all of the modules.The crystals that I have used one the modules are 26MHz and 24MHz. and the flashes are 32Mbit. the boot revision of AT commands are 1.2 and 1.5

What is the problem?

Thank you

[mvtdesign]

The problem of the second one and the third one is now solved, because I've replaced their Crystal with 2 new 26.000 MHz 10 ppm.

But still the first one doesn't work.

Any idea?