ModemManager connect fails due to multiple-connection-to-same-pdn-not-allowed
My L5 often gets into a state where ModemManager makes many failed connection attempts, it tries the same thing again and again and fails in the same way each time.
Example output from sudo journalctl -u ModemManager
:
dec 12 15:22:11 pureos ModemManager[578]: <info> [modem5] simple connect started...
dec 12 15:22:11 pureos ModemManager[578]: <info> [modem5] simple connect state (4/8): wait to get fully enabled
dec 12 15:22:11 pureos ModemManager[578]: <info> [modem5] simple connect state (5/8): register
dec 12 15:22:11 pureos ModemManager[578]: <info> [modem5] simple connect state (6/8): bearer
dec 12 15:22:11 pureos ModemManager[578]: <info> [modem5] simple connect state (7/8): connect
dec 12 15:22:11 pureos ModemManager[578]: <info> [modem5] state changed (registered -> connecting)
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer238] couldn't start network: QMI protocol error (14): 'CallFailed'
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer238] call end reason (1): generic-unspecified
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer238] verbose call end reason (6,55): [3gpp] multiple-connection-to-same-pdn-not-allowed
dec 12 15:22:12 pureos ModemManager[578]: <warn> [modem5/bearer238] connection attempt #1 failed: QMI protocol error (14): 'CallFailed'
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] state changed (connecting -> registered)
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer238] connection #1 finished: duration 0s, tx: 0 bytes, rx :0 bytes
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect started...
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (4/8): wait to get fully enabled
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (5/8): register
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (6/8): bearer
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (7/8): connect
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] state changed (registered -> connecting)
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer239] couldn't start network: QMI protocol error (14): 'CallFailed'
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer239] call end reason (1): generic-unspecified
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer239] verbose call end reason (6,55): [3gpp] multiple-connection-to-same-pdn-not-allowed
dec 12 15:22:12 pureos ModemManager[578]: <warn> [modem5/bearer239] connection attempt #1 failed: QMI protocol error (14): 'CallFailed'
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] state changed (connecting -> registered)
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer239] connection #1 finished: duration 0s, tx: 0 bytes, rx :0 bytes
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect started...
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (4/8): wait to get fully enabled
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (5/8): register
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (6/8): bearer
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (7/8): connect
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] state changed (registered -> connecting)
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer240] couldn't start network: QMI protocol error (14): 'CallFailed'
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer240] call end reason (1): generic-unspecified
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer240] verbose call end reason (6,55): [3gpp] multiple-connection-to-same-pdn-not-allowed
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer240] couldn't start network: QMI protocol error (14): 'CallFailed'
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer240] call end reason (1): generic-unspecified
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer240] verbose call end reason (6,55): [3gpp] multiple-connection-to-same-pdn-not-allowed
dec 12 15:22:12 pureos ModemManager[578]: <warn> [modem5/bearer240] connection attempt #1 failed: QMI protocol error (14): 'CallFailed'
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] state changed (connecting -> registered)
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer240] connection #1 finished: duration 0s, tx: 0 bytes, rx :0 bytes
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect started...
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (4/8): wait to get fully enabled
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (5/8): register
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (6/8): bearer
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] simple connect state (7/8): connect
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] state changed (registered -> connecting)
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer241] couldn't start network: QMI protocol error (14): 'CallFailed'
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer241] call end reason (1): generic-unspecified
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer241] verbose call end reason (6,55): [3gpp] multiple-connection-to-same-pdn-not-allowed
dec 12 15:22:12 pureos ModemManager[578]: <warn> [modem5/bearer241] connection attempt #1 failed: QMI protocol error (14): 'CallFailed'
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5] state changed (connecting -> registered)
dec 12 15:22:12 pureos ModemManager[578]: <info> [modem5/bearer241] connection #1 finished: duration 0s, tx: 0 bytes, rx :0 bytes
So, each time it says "verbose call end reason (6,55): [3gpp] multiple-connection-to-same-pdn-not-allowed".
It goes on with failed attempts like that for several hours, with hundreds of such failed connection attempts. I suspect it is the mobile data connection that fails, because I can make voice calls in spite of those failed connection attempts.
What does this mean? How to troubleshoot this further?
The "multiple-connection-to-same-pdn-not-allowed" makes it sound as if there is some existing connection, could I check that somehow? If there is an existing connection, why is ModemManager trying (and failing) to make a new connection?