I had this issue when trying to join server on localhost.
(Notes: You must set dev_uselocalserver value to 1 at options.txt to run PocketMine and run MCPE on the same time)
and this is the log when im trying to join.
mcpelauncher's log
[MinecraftPE] VERBOSE RAKNET [IPv6] multicast listen on interface 0
Signal 11 received
Getting stacktrace...
Backtrace elements: 3
#0 ./mcpelauncher(_Z12handleSignali+0x6d) [0x5663fd68]
#1 [0xf7796cb0]
#2 HYBRIS Level::getRuntimeEntity(EntityRuntimeID, bool) const+63 in libminecraftpe.so+0xe3bd9f [0xf561dd9f]
Signal 6 received
Aborted (core dumped)
Server's log
[11:02:54] [Server thread/INFO]: WasHere[/127.0.0.1:35498] [ClientID: -1367737555013045120] logged in with entity id 1 at (PinesForest, 128.5, 4, 128.5)
[11:03:04] [Server thread/INFO]: WasHere[/127.0.0.1:35498] logged out due to timeout
I had this issue when trying to join server on localhost. (Notes: You must set dev_uselocalserver value to 1 at options.txt to run PocketMine and run MCPE on the same time)
and this is the log when im trying to join.
mcpelauncher's log
Server's log