Target_frame does not exist but its found by tf2_tools echo.

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Hello everyone! I'm facing an strange issue with the code below. It's suposed to get the distance between two apriltag tags but it reports that the target frame doesn't exist.

I searched in http://wiki.ros.org/tf2/Tutorials/Deb... but everything looks correct for me. Even if I wait a lot the transformation between the two tags never becomes available.

import tf2_ros
import tf_conversions
import geometry_msgs
import rospy
from math import pi
import time

rospy.init_node('treeLink')
print("Nó iniciado")
tfBuffer = tf2_ros.Buffer(rospy.Duration(secs=2))
listener = tf2_ros.TransformListener(tfBuffer)
print("Listener iniciado")
br = tf2_ros.TransformBroadcaster()
print("Broadcaster iniciado")

    rate = rospy.Rate(10.0)

    syncTime = 0

    last_published_timestamp = rospy.Time(0)

    tree_link = geometry_msgs.msg.TransformStamped()

    tags = ["tag_0","tag_1","tag_2","tag_3","tag_4"] 

    while not rospy.is_shutdown():
                for n in range(0,len(tags)):
                    (trans,rot) = tfBuffer.lookup_transform("tag_2",tags[n],rospy.Time())
                    print("----------------------------------------------------")
                    print("Posição atual da" + tags[n] +":")
                    print("Translação")
                    print(trans)
                    print("Rotação")
                    print(rot)
            # except:
                if time.time() - syncTime > 1:
                    syncTime = time.time()
                    print("...")

matheus@matheus:~/catkin_ws/src/main/scripts/testes$ python3 showTagPos.py

Traceback (most recent call last):

File "showTagPos.py", line 86, in <module> (trans,rot) = tfBuffer.lookup_transform("tag_2",tags[n],rospy.Time())

File "/opt/ros/noetic/lib/python3/dist-packages/tf2_ros/buffer.py", line 86, in lookup_transform return self.lookup_transform_core(target_frame, source_frame, time)

tf2.LookupException: "tag_2" passed to lookupTransform argument target_frame does not exist.

matheus@matheus:~/catkin_ws/src/main/scripts/testes$ rosrun tf2_tools echo.py tag_2 tag_0

At time 3560.65, (current time 3560.72)

• Translation: [0.543, 0.218, -0.027]
• Rotation: in Quaternion [0.066, -0.187, 0.041, 0.979] in RPY (radian) [0.122, -0.380, 0.061] in RPY (degree) [6.985, -21.761, 3.481] At time 3560.65, (current time 3560.72)
• Translation: [0.543, 0.218, -0.027]
• Rotation: in Quaternion [0.066, -0.187, 0.041, 0.979] in RPY (radian) [0.122, -0.380, 0.061]