Problem with reading energymeter iskraemeco MT880

I have a problem reading the Iskraemeco meter MT880. Here is my setup:
- manufacturer: Iskraemeco
- Interface: HDLC
- authentication: low
- password: 51525354
- Wait time: 00:00:10
- Address Type: Default
- Logical server: 1
- Media: Net
- Logical Name Referancing - check
- Client Address: 1
- Resend count: 3
- Physical Server: 39 (Serial number: 76959423)
- Media: Net
- Host name: 10.249.11.4
- Port: 4003
- Protocol: TCP

Communication logs:

16:38:17 Send SNRM request.
TX: 7E A0 08 02 4F 03 93 D0 D4 7E
16:38:18
RX: 7E A0 1F 03 02 4F 73 36 BD 81 80 12 05 01 9A 06 01 9A 07 04 00 00 00 01 08 04 00 00 00 01 CC A2 7E
16:38:18 Send AARQ request.
TX: 7E A0 45 02 4F 03 10 15 DF E6 E6 00 60 36 A1 09 06 07 60 85 74 05 08 01 01 8A 02 07 80 8B 07 60 85 74 05 08 02 01 AC 0A 80 08 35 31 35 32 35 33 35 34 BE 10 04 0E 01 00 00 00 06 5F 1F 04 00 62 1E 5D FF FF 0B 2F 7E
16:38:18
RX: 7E A0 26 03 02 4F 30 1C 48 E6 E7 00 61 17 A1 09 06 07 60 85 74 05 08 01 01 A2 03 02 01 01 A3 05 A1 03 02 01 0D AE 4F 7E
16:38:18
RX: 7E A0 1F 03 02 4F 73 36 BD 81 80 12 05 01 9A 06 01 9A 07 04 00 00 00 01 08 04 00 00 00 01 CC A2 7E

Error appears:
Connection is permanently rejected. Authentication failure.
What could be the cause of this error? Other Iskra counters that I have read so far have worked on such settings. Is there a default password for reading these counters?