Sending mail panics with core dump when mail recipient is not set.

[mikedavison]

Note: Using the example code "Send_Text.ino" will reproduce problem.
I found that with my code if I have the line message.addRecipient(F("Mike"), RECIPIENT_EMAIL); all works fine.
However if i forget or comment out the line and no recipient is set, I get the error some of the recipient Email address is not valid.
This error message is expected but immediately after it prints the error message I get a core dump and reboot as below.

#### Error, some of the recipient Email address is not valid
Guru Meditation Error: Core  1 panic'ed (LoadProhibited). Exception was unhandled.
<< dump information redacted>>

Is this as designed or a bug? I would have expected it to neatly handle an error like this without a crash.

[mobizt]

Thanks for reporting this.

The library was updated to v3.4.21 with issue fixed, now you can update.