I can’t replicate exactly what happened, but hopefully my chaotic story may help anybody.
While waiting for a licence for my DMR repeater, I was running a high power hotspot with two Motorolas, pi-star and MMDVM from BJ7JTA. I was given a SSID from radioid.net and I was connected to the Brandbeister. Hotspot was working in duplex and in the private (not public) mode. When I received my licence for repeater, I reprogrammed frequencies in my Motorolas, I reprogrammed pi-star from private to public, I changed the SSID from my personal to the repeater one and… it stopped working. I mean from Brandmeister DMR point of view all was OK, my TX was transmitting the signal into my handheld radio and I was decoding the transmission. However when I was trying to send any signal from my handheld radio into the system, my MMDVM PCB was NOT decoding anything. So cable fault? SO I went into the mmdvmcal service mode and I found that my MMDVM decodes with no problem at all in the service mode! WTF? After hours of fighting and with BIG help from G4NAB I found that the whitelist was blocking me.
How to remove it?
SSH, cd /etc (entering catalog etc), rpi-rw (making SD card writable), sudo nano mmdvmhost (editing the file, remove the whitelist line completely) and press ctrl+x to exit the file, press y to confirm you want to save changes, rpi-ro to make it write only again. All done and my DMR repeater started working again!