Add this.siteURL to all emails and provide all variables in toolboxes
1) Add this.siteURL parameter to all emails liquid context. The parameter should appear here in the toolbox (https://prnt.sc/hdl6H0MHqPLq).
It should contain protocol and domain (save that domain for the email that was used by the site visitor when email sending was scheduled).
List of emails:
form autoresponders;
system emails;
custom emails and custom workflows.
2) Provide toolboxes (https://prnt.sc/ru2bmo) to all emails with the list of variables that is accessible on this object in liquid context for:
form autoresponders;
system emails;
custom emails.