Tasmota MQTT connection issue

Cannot connect to Thingspeak MQTT and publish to a channel. I receive the following error message:

Connect failed to mqtt.thingspeak.com:1883, rc 5. Retry in 10 sec

Here are my MQTT settings. Passwork I am using is the MQTT API key. Any help suggestion would be appreciated.

[Vinod]

I'm not familiar with the request that Tasmota is making to the ThingSpeak servers. Where in the configuration do you specify your channel's Write API key? What about the field values -- where are they specified?

Also, have you tried to reach out to the Tasmota developers -- they might have some suggestions since the configuration is happening in their software.