No bluetooth connection to SM Tripower

I succesfully installed SBFspot in 2018 and it logged the data from my Sunny Tripower 7000TL-20 using the usual cronjobs. I just realized that it stopped working on 6th Jan 2019 (SBFspot.cfg is unchanged since 2018). When executing

/usr/local/bin/sbfspot.3/SBFspot -v -finq -nocsv

I get

Connecting to 00:80:25:3A:78:0B (10/10)
Sun Feb 24 13:51:34 2019: CRITICAL: bthConnect() returned -1

The bt seems to be up as

sudo hcitool scan

results in

Scanning …
00:80:25:3A:78:0B SMA002d SN: 305076149 SN30507614

Any idea why SBFspot cannot establish the BT connection any more? The system is raspian stretch.

Dit you ever find a solution for this issue, have the same issue with my Raspberry Pi 4:

Connecting to 00:80:25:18:80:63 (1/15)
Connecting to 00:80:25:18:80:63 (2/15)
Connecting to 00:80:25:18:80:63 (3/15)
Connecting to 00:80:25:18:80:63 (4/15)
Connecting to 00:80:25:18:80:63 (5/15)
Connecting to 00:80:25:18:80:63 (6/15)
Connecting to 00:80:25:18:80:63 (7/15)
Connecting to 00:80:25:18:80:63 (8/15)
Connecting to 00:80:25:18:80:63 (9/15)
Connecting to 00:80:25:18:80:63 (10/15)
Connecting to 00:80:25:18:80:63 (11/15)
Connecting to 00:80:25:18:80:63 (12/15)
Connecting to 00:80:25:18:80:63 (13/15)
Connecting to 00:80:25:18:80:63 (14/15)
Connecting to 00:80:25:18:80:63 (15/15)
Sun Feb 27 11:04:15 2022: CRITICAL: bthConnect() returned -1
Sun Feb 27 11:04:15 2022: INFO: Done.

If possible, move the RPi closer to the inverter.
Make sure BT on RPi is not used by another process