Cannot save template + Cannot send mails + Fatal error

Dear Dev hello,

I will try to clearly describe and structure my problem(s).

1) I recently got an issue, for no reason, the mails do not send the PDF anymore.

2) I manualy tried to send a regular mail from an invoice, and wordpress whos a fatal error.”There has been a critical error on this website. Please check your site admin email inbox for instructions.”

3) I then manualy tried to send a mail trough the plugin (the small mail icon on the order edit). Same problem, red shield with “an unexpected error occur, please try again”.

4) I disable plugins 1 by 1 and found it the problem comes from “woo-pdf-invoice-builder”.

5) After disabling it, I’m able to resend the notification mails for the invoices.

6) I just update plugin to last version but still the same issue.

7) I also figured out I cannot edit the template. Well I actualy can edit but I cannot save it. It keep running fool forever.

Any idea? Any solution? Nothing seems to had chanced since then and few days ago it worked just fine.

Many thanks in advance for your help,
With regards,