# Getting Error While Connecting Ignition With UaExpert **URL:** \ **Category:** Ignition\ **Created:** [December 3, 2021, 11:02am UTC](https://forum.inductiveautomation.com/t/getting-error-while-connecting-ignition-with-uaexpert/53723 "2021-12-03T11:02:06Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Chinmay\_Marulkar](https://avatars.discourse-cdn.com/v4/letter/c/ba8739/32.png) [@Chinmay\_Marulkar](https://forum.inductiveautomation.com/u/Chinmay_Marulkar)\ **Post date:** [December 3, 2021, 11:02am UTC](https://forum.inductiveautomation.com/t/getting-error-while-connecting-ignition-with-uaexpert/53723/1 "2021-12-03T11:02:06Z")
Hello Everyone, Ignition OPC is installed on one server. UaExpert is installed on other server. Both the servers are in same office. Now when I am trying to connect Ignition from UaExpert I am getting an error message. Please find the attached image for your reference. Please help me to resolve this problem. Thanks, Chinmay Marulkar ![Image_1](https://us1.discourse-cdn.com/inductiveautomation/original/3X/5/4/546127957899527e7f2496505a5fa22581d0a24a.png) ---
**Author:** ![kcollins](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kcollins/32/19646_2.png) [@kcollins](https://forum.inductiveautomation.com/u/kcollins)\ **Post date:** [December 3, 2021, 3:56pm UTC](https://forum.inductiveautomation.com/t/getting-error-while-connecting-ignition-with-uaexpert/53723/2 "2021-12-03T15:56:20Z")
When making a secure connection to Ignition’s OPC Server, standard certificate validation aspects apply. If you’re getting a hostname mismatch, it is possible that you’re trying to access the endpoint by a different DNS name than is configured in the server certificate. You can take a look here to download your Ignition OPC Server certificate for inspection or regenerate it with new IP/DNS Subject Alternative Name (SAN) entries. ![2021-12-03 at 9.41 AM](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/9/8913fed5321507d2dc15b79d5b6fd6eb0fa32e29.png) You’ll want to look at the details of that cert, specifically the Subject Alternative Name (SAN) details: Windows: ![Screenshot 2021-12-03 094936](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/f/9f1f962a7a64ca7542705fe28969c525cfac3541.png) macOS/Linux: ``` openssl x509 -inform DER -in ignition-server.der -text -noout ``` ![2021-12-03 at 9.54 AM](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/e/1eee380e4e5260e09ad5364722502454be5b0705.png) ---
**Author:** ![Chinmay\_Marulkar](https://avatars.discourse-cdn.com/v4/letter/c/ba8739/32.png) [@Chinmay\_Marulkar](https://forum.inductiveautomation.com/u/Chinmay_Marulkar)\ **Post date:** [December 7, 2021, 12:53pm UTC](https://forum.inductiveautomation.com/t/getting-error-while-connecting-ignition-with-uaexpert/53723/3 "2021-12-07T12:53:35Z")
Hello Kcollins, Thank you so much for your swift response. I have regenerated the certificate with suggested way & attached snap for your reference. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/c/c/cc90444e9ec3bc37c5f0e0df616b68d6e9e0e0ff.png) Same certificate I have installed on other server i.e. on which UaExpert is installed. Did all the required activities & still the problem is same. Please let me know if any other checks need to be done to solve this case. Thanks, Chinmay Marulkar ---
**Author:** ![Chinmay\_Marulkar](https://avatars.discourse-cdn.com/v4/letter/c/ba8739/32.png) [@Chinmay\_Marulkar](https://forum.inductiveautomation.com/u/Chinmay_Marulkar)\ **Post date:** [December 20, 2021, 1:00pm UTC](https://forum.inductiveautomation.com/t/getting-error-while-connecting-ignition-with-uaexpert/53723/4 "2021-12-20T13:00:16Z")
Hello, I need a help on priority. Requesting you to please help me ASAP… I already tried to add entries in HOST file, but still there is a same error. Thanks, Chinmay Marulkar ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [December 20, 2021, 2:05pm UTC](https://forum.inductiveautomation.com/t/getting-error-while-connecting-ignition-with-uaexpert/53723/5 "2021-12-20T14:05:51Z")
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**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [December 20, 2021, 2:44pm UTC](https://forum.inductiveautomation.com/t/getting-error-while-connecting-ignition-with-uaexpert/53723/6 "2021-12-20T14:44:58Z")
On recent versions of Ignition you should get prompted to explicitly add IP or DNS names to the certificate when regenerating: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/c/ac81374c5c53735bc3033ec74adb71a0580ae800.png) Otherwise you can: 1. ignore the UaExpert warning. It’s just a warning, you can connect anyway. 2. connect using the IP address listed in the certificate instead. 3. connect using the hostname listed in the certificate instead. You do need to restart Ignition after regenerating certificates.