Basically, I was unable to add an exchange account to my phone.
I had this error from testconnectivity.microsoft.com – HTTP 500 Internal Server Error
In the logs was this error:
2019-06-18 22:03:39 10.0.0.242 POST /Microsoft-Server-ActiveSync/default.eas Cmd=FolderSync&User=username&DeviceId=1560557047&DeviceType=TestActiveSyncConnectivity&Log=V120_St:F_Srv:19a0c0d0s0e0r0A0sd_LdapC1_RpcC76_RpcL78_Ers1_Cpo19890_Fet19998_S111_Mbx:server_Throttle0_Budget:(D)Conn%3a1%2cHangingConn%3a0%2cAD%3a%24null%2f%24null%2f1%25%2cCAS%3a%24null%2f%24null%2f1%25%2cAB%3a%24null%2f%24null%2f0%25%2cRPC%3a%24null%2f%24null%2f1%25%2cFC%3a1000%2f0%2cPolicy%3aDefaultThrottlingPolicy%5Fee41c844-cbea-4dde-a7b7-74c88fb0e058%2cNorm%5bResources%3a(Mdb)Users01(Health%3a-1%25%2cHistLoad%3a0)%2c(DC)dc(Health%3a-1%25%2cHistLoad%3a0)%2c%5d_ 443 user 18.104.22.168 Microsoft-Server-ActiveSync/12.0+(TestExchangeConnectivity.com) 500 0 0 20232
After digging into logs and internet I found out that the problem was caused by insufficient rights to the exchange system.
To solve it, I did 2 actions:
1 – Remove adminCount from my account in AD (It was 1)
2 – Enable security inheritance for my account in AD