I am sending data to a website with Arduino + SIM800L in json format. On the web a php program decodes json and writes the data in a file. (I use a SIM from Things Mobile)

Everything works fine, but I get an error: AT + HTTPINIT -> ERROR

I do not know how important that is, because despite this, the data goes well to the web.

Why can that error be? How can I solve?

This command is called only once after Internet enabled, May be you are calling it in a loop so the error.