Cellular data connection fails

[Tim Seppelt]

I can't use my cellular data connection any more. The problem occurred after upgrading to OTA 12 but not directly afterwards. I use 2 sim cards (SIM 1 congstar for calls, SIM 2 orange for cellular data). System-settings shows me that only one of them (the one which I don't want to use for cellular data) can be found. This affects only the cellular data section. I can use it for calling and text messages.

I tried to delete several config / cache files and to swap the sim cards.

I think this line in /var/log/syslog shows the problem:
Aug 8 16:49:36 ubuntu-phablet ofonod[2115]: ril_data_reg_cb: DATA_REGISTRATION_STATE reply failure: GENERIC_FAILURE

[Tim Seppelt (t-seppelt)]

Details about my phone:

BQ Aquaris E4.5
Ubuntu 15.04 (OTA-12)
Build Ubuntu 15.04 armhf (20160708-091336)
20160606-ab415b2
KRILIN01A-S15A_BQ_L100EN_2034_160708
20160701-981-38-14