Outlook settings for certificates
For some time now, Mozilla Thunderbird no longer accepts almost all digitally signed mails sent with Outlook at TU Dortmund University. The reason is the default use of SHA1 as hashing algorithm by Outlook.
This can be avoided by changing the value for the hash algorithm from SHA1 to SHA256 in Outlook in the Trust Center in the settings for e-mail security via "Change security settings".
TU members can find a detailed description of how to digitally sign mails with Outlook in the ServicePortal: