MSGID: 2:221/360.0 5e110de2
REPLY: 2:221/360.0 5e110554
PID: JamNNTPd/OS2 1.3 20191208
TID: GE/2 1.2
CHRS: UTF-8 2
TZUTC: 0200
On 04/01/2020 4:36 p.m., Tommi Koivula : August Abolins wrote:

>> Enigmail Security Info Part of the message signed Unverified signature
>> Public key D22932992A6F822A used to verify signature BAD signature
>> from Tommi Koivula 
>>
>> Why would it be BAD?
>
> I'm not sure but it may be because of the way how JamNNTPd shows the
> From: field.

More info:

This message that you wrote here..

X-JAM-From: Tommi Koivula <2:221/360.0>
X-JAM-To: Wilfred van Velzen
X-JAM-MSGID: 2:221/360.0 5e10f2b2
X-JAM-REPLYID: 2:280/464 5e10cfa1
  --- Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101
  Thunderbird/68.3.1
 + Origin: nntp://rbb.fidonet.fi - Lake Ylo - Finland (2:221/360.0)

...reports GOOD:

Enigmail Security Info Part of the message signed Good signature from
Tommi Koivula  Key ID:
0x413267ADA3AC401A18C023D2D22932992A6F822A / Signed on: 01/04/20, 3:16
PM Key fingerprint: 4132 67AD A3AC 401A 18C0 23D2 D229 3299 2A6F 822A
Used Algorithms: RSA and SHA256

But, you used a different system and editor for the one that reports BAD:

 + Origin: 2001:470:1f15:cb0:f1d0:2:221:1 (2:221/1)
 ..using GoldED


Maybe that is a clue.

--- Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 
hunderbird/60.9.1
 * Origin: nntp://rbb.fidonet.fi - Lake Ylo - Finland (2:221/360.0)
SEEN-BY: 1/123 19/10 90/1 203/0 221/0 1 6 360 227/114 229/426 1014
SEEN-BY: 240/5832 249/206 317 400 280/464 5003 292/854 8125 317/3
SEEN-BY: 322/757 335/364 342/200 423/81
PATH: 221/360 1 292/854 229/426