Reply to an email with address who has capital letters

Hello i love this soft but i have a bug

mail no longer leaves when asked to reply to an email with the email address of the recipient who has capital letters

Thank

I can’t replicate this using Mailspring 1.9.1 on Linux - sending an email to an all-caps address works fine for me. Can you provide more details, like a (redacted) email format that fails, mail host etc.?

this error occurs by replying an email from this address

From: Lauriane JASCHKE <Lauriane.JASCHKE@ConvergenceConsulting.fr>

Same thing happened to me recently. I had an error when I tried to send a mail to an address written in capital letters (NAME.SURNAME@gmail.com).
Modified the address in the contact book to be lower case only and it seems to work.