Using sim800l evb connected to pi zero w under Python. Sending sms function correctly. I try to send mms does not function. cmmscurl : mms.free.fr cmmsproto: 18.104.22.168 80 sapbr 3,1 apn: mmsfree cmmsdown returns : connect cmmssend returns : connection to the network is failed. carte sim in my phone: sms and mms function correctly. How can help me? thank.