Issue for ethr latency test of AWS EC2 in two different regions

If you set up two EC2 in tow AWS regions, and test latency between them, there is no any result comes out. Even though the connection is valid, but sees all of packages are dropped by some reason.
For instance: one EC2 in us-east-1, and the other in ap-southeast-1, you run command like below:

for server EC2:
./ethr -s --port 5023.
for client EC2:
./ethr -c xxxx.xxxx.xxxx.xxxx -n 16 --port 5023 -p tcp -t l

And you got nothing related to valid result, but the connection is ok.

If you put two EC2 in the same region, and do the same test, and you will get the expected result..

I noticed that AWS has a MTU 1500 bytes restriction for traffic over an internet gateway, so my question is does ethr latency test will send a package over the 1500 bytes size? And how can I solve this issue

No source file or test is named. Start by reproducing the cross-region EC2 case with the shown ethr server and client commands, then trace the latency-test path and packet sizing. Done means the cross-region test produces a valid latency result while preserving the existing same-region behavior.