SIM800l Httpaction. Can't get 0,200 or 0,200 - embedded

Question

I'm playing with HTTP GET and POST methods and I have problem. My problem is next one: Last week my GET method was work perfect and then suddenly stop working. Problem occur because MCU can't got response in this format: 0,200,xxx. Code is identical 100%. MCU always got this response: 0,603 (DNS error). Next commands and responses I send/receive to/from SIM800l:
Signal strength | at command: AT+CSQ | response +CSQ: 20,0
Full functionality | at command: AT+CFUN=1 | response OK
If bearer is open send | at command: AT+SAPBR=0,1 | response OK
Otherwise do nothing
Set bearer for gprs | at command: AT+SAPBR=3,1,"CONTYPE","GPRS" | response OK
Set APN | at command: AT+SAPBR=3,1,"APN","internet" | response OK
Set USERNAME | at command: AT+SAPBR=3,1,"USER","telenor" | response OK
Set PASSWORD | at command: AT+SAPBR=3,1,"PWD","gprs" | response OK
Is bearer opened | at command: AT+SAPBR=2,1 | response +SAPBR: 1,3,"0.0.0.0"
Open bearer | at command: AT+SAPBR=1,1 | response OK
Init http | at command: AT+HTTPINIT | response OK
Enable SSL | at command: AT+HTTPSSL=1 | response OK
Set profile identifier | at command: AT+HTTPPARA="CID",1 | response OK
Set url | at command: AT+HTTPPARA="URL","https://mondo.rs/" | response OK
Set GET action | at command: AT+HTTPACTION=0 | response 0,603,0
When I got this response I send again same at command, and result is same (sometimes response from SIM800l is 0,604,0). I use laboratory psu ( which is stable and enough for SIM800l).
Stiil I can send SMS, read all messages,.. without problem. What can be problem?

Answer 1

I find solution for problem, mainly sim800l need firmware upgrade.
Follow steps:
Download SIM800_Series_download_Tools_Customer_v1.19.rar(for win) https://simcom.ee/documents/?dir=SIM800x and driver MTK_USB_DRIVER.rar
Look what firmware is currently on sim800 with AT+CGMR, my firmware was 1418B02SIM800L24. Here B02 is interested for us.
sim800l have 2 different hardware models L16 and L24. If your firmware version have L16 on the end of firmware mark download new firmware from https://simcom.ee/documents/?dir=SIM800L. Otherwise (L24) download new firmware from https://letmeknow.fr/blog/2018/01/09/tuto-update-firmware-sim8xx/. I know that is French blog but only there I find firmware for sim800l model L24. After uploading new firmware and calling AT+CGMR you will get 1418B05SIM800L24. So now firmware version is B05 and you can send(get) messages to the web-sites without problem.
Don't forget that this module is 2G and receiving characters from modern https web-site will take some time (a few tenths of a second).