@amirrrrez 

Hi, is the international roaming service enabled for your SIM card as well? 

Please insert the same SIM card into your phone in Germany and test if it works fine on the phone and which network it picks up in Germany.

If it works fine on the phone, please insert it back into the MR200, try to check if the APN profile settings are correct or not on Advanced->Network->Internet page, if not, try to create a profile manually and enter the APN etc. manually to see if it works.

If it still doesn't work, please share with us screenshots of Advanced->Status page and Advanced->Network->Internet page.