ACME run renew show error message.

[akong]

Hello,
I installed acme package and setup manual dns all done.
When I run renew.It's show follow error message.

[Thu Jul 20 09:21:27 CST 2017] Renew: 'eta-gateway.xxx.com'
[Thu Jul 20 09:21:27 CST 2017] Single domain='eta-gateway.xxx.com'
[Thu Jul 20 09:21:27 CST 2017] Getting domain auth token for each domain
[Thu Jul 20 09:21:27 CST 2017] Verifying:eta-gateway.linguitronics.com
[Thu Jul 20 09:21:29 CST 2017] eta-gateway.xxx.com:Challenge error: {"type":"urn:acme:error:malformed","detail":"Unable to update challenge :: The challenge is not pending.","status": 400}
[Thu Jul 20 09:21:29 CST 2017] Please check log file for more details: /tmp/acme/eta-gateway/acme_issuecert.log

Is the acme server problem?Or another question?