nRF9160 - no LTE-NB connection [LTE Link Monitor]

Question

Dear Nordic, dear Community, 
 I want to use the NRF9160 for a new IoT product row of our company. 
 The NRF9160 DK seems the perfect solution for evaluation and development of our solution. 
 
 Unfortunately I am not able to connect to a LTE-NB network. 
 I have updated the Modem Firmware to mfw_nrf9160_1.1.1 (current version) and programmed the NRF with the nrf9160dk_at_client_2019-11-29_d3130d77.hex firmware (full image) via the NRF connect programmer sw tool. 
 I am using a SIM from Fusion-IOT, according to the provider we should have a LTE-NB signal here in south germany (SIM can use every national NB net). I've tested the following at home, in my company and at the University of Stuttgart, each time, also with the Basis eSIM with same (bad) results (yes i changed the switch between E-sim and sim): 
 In the LTE Link Monitor im giving the AT commands AT%XSYSTEMMODE=0,1,1,0 //for LTE-NB usage 
 and AT+CGDCONT=0,"IP","m2m.fusion-iot.de" //for selecting the APN of my SIM provider 
 after giving AT+CFUN=1 and AT+CFUN? im getting the usual feedback but when there is a signal (according to CEREG) the NRF tries to connect, the LTE indicator Box switches between orange and red for <1s and then I'm getting CEREG 4 (unknown, e.g. out of E-UTRAN range) with a grayed out LTE indicator box. Does anyone know what this means? Is there an hardware issue or did i make anything wrong? 
 AT+COPS=? returns +CME ERROR: 0 
 It would be great if anyone can help me or had this issue before. Thank you in advance, 
 Niko

LTE Link Monitor Terminal: 
 
 // ... 
 // 
 // ... 
 
 ***** Booting Zephyr OS build v2.0.99-ncs1 ***** 
 The AT host sample started 
 AT%XSYSTEMMODE=0,1,1,0 
 OK 
 AT+CGDCONT=0,"IP","m2m.fusion-iot.de" 
 OK 
 AT+CFUN=1 
 OK 
 AT+CFUN? 
 +CFUN: 1 
 OK 
 AT+CGSN=1 
 +CGSN: "352656100303646" 
 OK 
 AT+CGMI 
 Nordic Semiconductor ASA 
 OK 
 AT+CGMM 
 nRF9160-SICA 
 OK 
 AT+CGMR 
 mfw_nrf9160_1.1.1 
 OK 
 AT+CEMODE? 
 +CEMODE: 0 
 OK 
 AT%XCBAND=? 
 %XCBAND: (1,2,3,4,5,8,12,13,17,19,20,25,26,28,66) 
 OK 
 AT+CMEE? 
 +CMEE: 0 
 OK 
 AT+CMEE=1 
 OK 
 AT+CNEC? 
 +CNEC: 0 
 OK 
 AT+CNEC=24 
 OK 
 AT+CGEREP? 
 +CGEREP: 0,0 
 OK 
 AT+CGDCONT? 
 +CGDCONT: 0,"IP","m2m.fusion-iot.de","",0,0 
 OK 
 AT+CGACT? 
 +CGACT: 0,0 
 OK 
 AT+CGEREP=1 
 OK 
 AT+CIND=1,1,1 
 OK 
 AT+CEREG=2 
 OK 
 AT+CEREG? 
 +CEREG: 2,4,"FFFE","FFFFFFFF",9 
 OK 
 AT%CESQ=1 
 OK 
 AT+CESQ 
 +CESQ: 99,99,255,255,255,255 
 OK 
 AT%XSIM=1 
 OK 
 AT%XSIM? 
 %XSIM: 1 
 OK 
 AT+CPIN? 
 +CPIN: READY 
 OK 
 AT+CPINR="SIM PIN" 
 +CPINR: "SIM PIN",3 
 OK 
 AT+CIMI 
 232010869981139 
 OK 
 %CESQ: 48,2,23,3 
 +CEREG: 2,"D2F5","01C4D009",9 
 +CNEC_EMM: 15 
 +CEREG: 4,"D2F5","01C4D009",9 
 %CESQ: 255,0,255,0 
 +CEREG: 4,"FFFE","FFFFFFFF",9 
 %CESQ: 51,2,22,3 
 +CEREG: 2,"BAD1","0113AA65",9 
 +CNEC_ESM: 111,0 
 +CNEC_EMM: 15 
 +CEREG: 4,"BAD1","0113AA65",9 
 %CESQ: 255,0,255,0 
 +CEREG: 4,"FFFE","FFFFFFFF",9 
 %CESQ: 49,2,22,3 
 +CEREG: 4,"BAD1","0113AA65",9 
 %CESQ: 49,2,27,3 
 %CESQ: 49,2,32,4