Help with this Internal Error

I set the same email address for two businesses. Both were tested fine. But this error comes preventing the sending of emails. Could you clarify why it is so?
Thank you so much

Can you clarify when and what actions you take to provoke this error?

Whaet editon of Manager are you using - Server, Desktop or Cloud?

Cloud version. Nothing other than using the same email address for two businesses. Thanks

Show the edit screen of the Email Settings page

I meant what causes the error to appear - what action did you do to provoke it?

Again, illustrate witha few screen shots

This is related to internal PDF generator which is no longer supported.

See: Internal PDF generator now obsolete

Thanks a lot both. May know the solution please?

The solution is here:

That is great, but when I sent the link…link did not appear in the mail. Is there any security reason from Gmail for that effect? Please

Now it is working however. Thank you so much for the prompt reply. Have a nice day.