I am new in this forum as well as with ESP8266. I had exactly the same problem as discussed in this post.
Yesterday I found the final hint in another post viewtopic.php?f=45&t=10368&start=16 [/b] by PeterN.
The problem seems connected to the chip vendor. I have 2 WeMos D1 Mini labeled with HYSIRY which means Shenzhen Hysiry Technology Co., Ltd.
Before I used ESP_Basic_Flasher and esptool / flash.cmd from ESPEasy which both are loading other firmware without problems. After flashing the 4MB ESPBasic with NODEMCU FIRMWARE programmer ESP8266Flasher.exe my boards are working perfectly.
When the board is loaded correctly the LED flashes a second time approx 30 sec. after reset !
I then used the NodeMCU ESP8266Flasher.exe, along with an ESP8266 firmware binary, and the flash worked! Immediately the AP appeared. My problem is now locating an up to date binary - mine's an old V2.0 version.
Hope this helps.