Ontap cannot connect to the cluster with Error number 5 (EONTAPI_EIO) after upgraded to 9.1P9

ZhengCai — Wed, 04 Jun 2025 14:12:52 GMT

Hi,

My client code (C++) using ONTAP API (management SDK 5.5) worked fine with the cluster (running 8.3) before.

But after the cluster is upgraded to 9.1P9, the client cannot connect to the cluster with the following error:

Can't connect to host (err=5)

I also tried upgrading my management SDK to 9.3, but it failed with the same error.

Any idea on what is going wrong, and how should I fix this? Is it because the Ontap server is not running properly? If so, how should I diagnose in this case?

Thank you very much in advance.

PS: I am also attaching the tcpdump log when the client was trying to connect, just in case it might help:

15:17:37.297091 IP (tos 0x0, ttl 64, id 56756, offset 0, flags [DF], proto TCP (6), length 60)

client_hostname.38530 > netapp_cluster_hostname.https: Flags [S], cksum 0x6b7d (incorrect -> 0x8c2e), seq 4280977165, win 26880, options [mss 8960,sackOK,TS val 1359436473 ecr 0,nop,wscale 7], length 0

15:17:37.297390 IP (tos 0x0, ttl 63, id 45324, offset 0, flags [DF], proto TCP (6), length 60)

netapp_cluster_hostname.https > client_hostname.38530: Flags [S.], cksum 0x40cb (correct), seq 1555209334, ack 4280977166, win 65535, options [mss 8960,nop,wscale 6,sackOK,TS val 2784367924 ecr 1359436473], length 0

15:17:37.297411 IP (tos 0x0, ttl 64, id 56757, offset 0, flags [DF], proto TCP (6), length 52)

client_hostname.38530 > netapp_cluster_hostname.https: Flags [.], cksum 0x6b75 (incorrect -> 0x8c10), seq 1, ack 1, win 210, options [nop,nop,TS val 1359436473 ecr 2784367924], length 0

15:17:37.300312 IP (tos 0x0, ttl 64, id 56758, offset 0, flags [DF], proto TCP (6), length 347)

client_hostname.38530 > netapp_cluster_hostname.https: Flags [P.], cksum 0x6c9c (incorrect -> 0xa5f5), seq 1:296, ack 1, win 210, options [nop,nop,TS val 1359436476 ecr 2784367924], length 295

15:17:37.500489 IP (tos 0x0, ttl 64, id 56759, offset 0, flags [DF], proto TCP (6), length 347)

client_hostname.38530 > netapp_cluster_hostname.https: Flags [P.], cksum 0x6c9c (incorrect -> 0xa52c), seq 1:296, ack 1, win 210, options [nop,nop,TS val 1359436677 ecr 2784367924], length 295

15:17:37.500741 IP (tos 0x0, ttl 63, id 45326, offset 0, flags [DF], proto TCP (6), length 52)

netapp_cluster_hostname.https > client_hostname.38530: Flags [.], cksum 0x7ffe (correct), seq 1575, ack 296, win 1024, options [nop,nop,TS val 2784368127 ecr 1359436677], length 0

15:18:56.676793 IP (tos 0x0, ttl 63, id 46685, offset 0, flags [DF], proto TCP (6), length 52)

netapp_cluster_hostname.https > client_hostname.38530: Flags [R.], cksum 0x4ab1 (correct), seq 1575, ack 296, win 1024, options [nop,nop,TS val 2784447303 ecr 1359436677], length 0

15:18:56.676829 IP (tos 0x0, ttl 64, id 56760, offset 0, flags [DF], proto TCP (6), length 52)

client_hostname.38530 > netapp_cluster_hostname.https: Flags [.], cksum 0x6b75 (incorrect -> 0x54d4), seq 296, ack 1, win 210, options [nop,nop,TS val 1359515853 ecr 2784367924], length 0

15:18:56.677093 IP (tos 0x0, ttl 63, id 46686, offset 0, flags [DF], proto TCP (6), length 40)

netapp_cluster_hostname.https > client_hostname.38530: Flags [R], cksum 0xb32a (correct), seq 1555209335, win 0, length 0

Re: Ontap cannot connect to the cluster with Error number 5 (EONTAPI_EIO) after upgraded to 9.1P9

dbenadib — Sat, 30 Dec 2017 20:01:33 GMT

Anything related to an expired certificate? On node or cluster vserver?

topic Re: Ontap cannot connect to the cluster with Error number 5 (EONTAPI_EIO) after upgraded to 9.1P9 in ONTAP Discussions

Ontap cannot connect to the cluster with Error number 5 (EONTAPI_EIO) after upgraded to 9.1P9

Re: Ontap cannot connect to the cluster with Error number 5 (EONTAPI_EIO) after upgraded to 9.1P9