Fix `SendMail` watchdog restart during reconnect to SMTP server (#21454)

CHANGELOG.md

@@ -28,6 +28,7 @@ All notable changes to this project will be documented in this file.
 - Webradio crash with invalid url (#21446)
 - Zigbee crash when removing `ZbName` (#21449)
 - ESP32 BLE fix scanning (#21451)
+- `SendMail` watchdog restart during reconnect to SMTP server (#21454)
 
 ### Removed
 - Support of old insecure fingerprint algorithm. Deprecated since v8.4.0 (#21417)

RELEASENOTES.md

@@ -141,6 +141,7 @@ The latter links can be used for OTA upgrades too like ``OtaUrl https://ota.tasm
 - Wrong timeout in `WebQuery` and `webclient` since Core3 [#21442](https://github.com/arendst/Tasmota/issues/21442)
 - Zigbee crash when removing `ZbName` [#21449](https://github.com/arendst/Tasmota/issues/21449)
 - Avoid connection errors when switching to safeboot to upload OTA firmware [#21428](https://github.com/arendst/Tasmota/issues/21428)
+- `SendMail` watchdog restart during reconnect to SMTP server [#21454](https://github.com/arendst/Tasmota/issues/21454)
 - ESP32 BLE fix scanning [#21451](https://github.com/arendst/Tasmota/issues/21451)
 - Webradio crash with invalid url [#21446](https://github.com/arendst/Tasmota/issues/21446)
 - Berry Leds matrix alternate more and error about 'bri' attribute [#21431](https://github.com/arendst/Tasmota/issues/21431)

tasmota/tasmota_xdrv_driver/xdrv_01_2_webserver_esp32_mail.ino

@@ -247,6 +247,9 @@ uint16_t SendMail(char *buffer) {
 
                 /* Connect to server with the session config */
                 delay(0);
+
+                smtp->closeSession();  // Fix watchdog due to long connection time (#21454)
+
                 if (smtp->connect(&session)) {
                   /* Start sending the Email and close the session */
                   delay(0);
@@ -264,7 +267,8 @@ uint16_t SendMail(char *buffer) {
     }
   }
 
-  if (smtp) { delete smtp; }
+  if (smtp) { delete smtp;
+  }
   for (uint32_t cnt = 0; cnt < MAX_ATTCHMENTS; cnt++) {
     if (attachments[cnt]) {
       free(attachments[cnt]);