Android MQTT Client not working "stream terminated by RST_STREAM with error code: PROTOCOL_ERROR

Hello,

i just want to set uop an Android MQTT Client.
I tested several clients in the google plaground store, but i cant get any connections.

With the PC-Program MQTT-Explorer i can get a connection.

I followed the intruction on the MQTT-Integration side.

I testet the Server with Server: eu1.cloud.thethings.network
Port: 1883. and also the IP-Adress 63.34.215.128

User name is application_id@ttn and password is the API-Key.

What can be the problem?

Greetings

E_T

Blockquote
{
“name”: “as.mqtt.connect.fail”,
“time”: “2023-02-25T09:14:13.277511820Z”,
“identifiers”: [
{
“application_ids”: {
“application_id”: “testnewjoin”
}
}
],
“data”: {
@type”: “type.googleapis.com/ttn.lorawan.v3.ErrorDetails”,
“message_format”: “stream terminated by RST_STREAM with error code: PROTOCOL_ERROR”,
“correlation_id”: “9f9a72bab6d4450d8edc49d8f7c4e19d”,
“code”: 13
},
“origin”: “ip-10-100-13-97.eu-west-1.compute.internal”,
“context”: {
“tenant-id”: “CgN0dG4=”
},
“visibility”: {
“rights”: [
“RIGHT_APPLICATION_TRAFFIC_READ”
]
},
“unique_id”: “01GT3XKWWXGW3PH3YNR4469GBX”
}

Have you tried port 8883 and you need to use TLS. And what version MQTT broker are you using?