Error sending threepid validation email ... yield send_email_func(email_address, token, client_secret, session_id) ValueError: unsupported format character 'S' (0x53) at index 7

[phtmgt]

Description

Cannot register with an e-mail address.

Steps to reproduce

• try to register with a supplied e-mail address
• 'An error was encountered when sending the email' error on frontend
• error in the title in backend

When trying to supply an e-mail at register, we get the error in the title.

Version information

• Homeserver: 1.5.1+bionic1

If not matrix.org:

• Version: 1.5.1+bionic1

• Install method: Debian through matrix-synapse repo

• Platform: Ubuntu 18.04

I already tried changing the shared_secret (remove '%' from it). Also checked email_address, token, client_secret, and session id, they don't have any strange characters, especially capital 'S'.

[phtmgt]

I was able to fix it, still believe this is a bug that should be addressed. Problem was in homeserver.yaml:

notif_from: "%(app) Server <matrix

changed it to:

notif_from: "%(app) server <matrix

and it worked.

Using capital S breaks the email sending, this seems like a very strange bug. Escape it somewhere in code or at least add a comment to the documentation (don't use a Capital S?).

[richvdh]

you need %(app)s, not %(app)

[phtmgt]

@richvdh Not really. The issue is completely different. I managed to find a workaround (my previous comment), but this is definitely a limitation that at least needs to be documented.

[richvdh]

Have you tried writing notif_from: "%(app)s Server <matrix... ?

[phtmgt]

This works:

"%(app) server <matrix

Probably your solution works as well. Just saying it's a good idea for it to be documented somehow (here in github or in homeserver.yaml comments).

[richvdh]

This works:

"%(app) server <matrix

are you sure? Have you checked what comes out? The placeholder for the app name is %(app)s. It is not %(app).

[richvdh]

@plamenh does https://github.com/matrix-org/synapse/pull/6423/files#diff-8b49bb218a1d7b96778287934cc311eaR1277 help to clarify that? Feel free to comment on that PR if you have further suggestions

[phtmgt]

Ok, you might have a point there. What I get in the from field is:

Matrixerver instead of Matrix server

With the s there it works as expected.