What can cause the trigger before-checkin [Comment Required] to fail even when I'm leaving a comment?

Question

So, I'm executing this command:

cm ci -c="Merge child branch"

And, here's the response:

The selected items are about to be checked in. Please wait ...
WARNING: the secure connection hostname provided in the server 
certificate doesn't match the server's hostname. This means that the 
certificate was not issued to this hostname or that there is a network 
configuration problem with this host.

- Certificate hostname: CN=ip-<obfuscated>
- Server hostname: CN=<obfuscated>

If you want to continue connecting to this host, choose 'Yes'. The certificate 
  validation will continue (not recommended).
If you want to abandon the connection, choose 'No' (recommended).

Choose an option (Y)es, (N)o (hitting Enter selects 'No'): y

The server you are connecting to has sent a certificate that is not in the 
store. This is normal if it is the first time that you connect to this server.

Certificate details: 
- Issued to: CN=ip-<obfuscated>
- Issued by: CN=ip-<obfuscated>
- Expiration date: 6/30/2023 6:15:40 AM
- Certificate hash:<obfuscated>

If you trust this host, choose 'Yes' to add the key to Plastic SCM's key store 
  (recommended if it is the first time you connect to this server).
If you want to carry on connecting just once, without adding the key to the 
  store, choose 'No'.
If you do not trust this host, choose 'Cancel' to abandon the connection.


Choose an option (Y)es, (N)o, (C)ancel (hitting Enter cancels): y
Assembling checkin data
Validating checkin data
Uploading file data
Confirming checkin operation
The trigger before-checkin [Comment Required] failed. .

In particular, that last line:

The trigger before-checkin [Comment Required] failed. .

But, I thought I was adding a comment. I don't think it's a syntax error. Where should I begin to debug this issue?

By the way, the same "comment required" error happens in the GUI as well even though I clearly have a comment in the comment box:

Answer 1

The Plastic server service I was connected to was down. In short, the first thing I should have done was contact the server administrator.

Note to self: Don't always think Stack Overflow is the only best way to solve your problems.