The URLs for html emails are fine, but the URLs in text mode are invalid (they are also extremely long).
Eg
From: Simon Fels <noreply@forum.snapcraft.io>
Reply-to: Simon Fels <noreply@forum.snapcraft.io>
To: jamie@canonical.com
Subject: [snapcraft.io] [snapd] Integrate snapd-xdg-open into snapd repository
Date: Mon, 10 Apr 2017 14:30:12 +0000 (04/10/2017 09:30:12 AM)
...
[Visit Topic](https://u5043074.ct.sendgrid.net/wf/click?upn=DoTHn2hO6rEn-2BtNmhkgbVz1CCJIYyT0eCnju-2B2t6pTMP7ZLG13A0du8PFgTFOOGGPDeWIpdvXQ2Pg5TlMs-2BBwFoy4vEpVAHY4gROLgE3Q5kSwLhF0txrr0XB-2FhIJC-2BwP_gQnR99KDF7Wcq96qvrkuPHUYhFSGIEfGcC6x6pTvmhCKy8qSf6IfowlYW7QL3cTkwaysPz-2FACsYH4H3Tpry7PzR-2BmANldfg56hTMagoTYCTrFpzMqIX12u13QrTcBHNdLxQa8ZmbOjVpUECXABvU1rBsKCBRrOAZkp7mWS5y8vE0pwwDWhBdIo344Ppmue-2BrFNfBisi6SV6JjqL-2BA6FkMuvQpDWgwf9Pv-2BSa9hgDQCU-3D to respond.
You are receiving this because you enabled mailing list mode.
...
If I copy and paste the above:
https://u5043074.ct.sendgrid.net/wf/click?upn=DoTHn2hO6rEn-2BtNmhkgbVz1CCJIYyT0eCnju-2B2t6pTMP7ZLG13A0du8PFgTFOOGGPDeWIpdvXQ2Pg5TlMs-2BBwFoy4vEpVAHY4gROLgE3Q5kSwLhF0txrr0XB-2FhIJC-2BwP_gQnR99KDF7Wcq96qvrkuPHUYhFSGIEfGcC6x6pTvmhCKy8qSf6IfowlYW7QL3cTkwaysPz-2FACsYH4H3Tpry7PzR-2BmANldfg56hTMagoTYCTrFpzMqIX12u13QrTcBHNdLxQa8ZmbOjVpUECXABvU1rBsKCBRrOAZkp7mWS5y8vE0pwwDWhBdIo344Ppmue-2BrFNfBisi6SV6JjqL-2BA6FkMuvQpDWgwf9Pv-2BSa9hgDQCU-3D
then it goes to βIntegrate snapd-xdg-open into snapd repository)β
Once I remove the trailing β)β it works fine. Making the URL work at all would be good, but making the URL look like what you see in the location bar would be even better.