Error when opening subnets in IPAM "An error has occurred Unterminated string. Expected delimiter: \". Path '[43].Id', line 1, position 4000."

When accessing subnets, the following error will occur.

error: {
      "message": "An error has occurred.",
      "exceptionMessage": "Unterminated string. Expected delimiter: \". Path '[43].Id', line 1, position 4000.",
      "exceptionType": "Newtonsoft.Json.JsonReaderException",
      "stackTrace": " at Newtonsoft.Json.JsonTextReader.ReadStringIntoBuffer(Char quote)\r\n at

If there are too many custom properties in the IPAM setting and UI Setting.SubnetIpsColumn value exceeded character limit (4000 characters).

To resolve this issue, please upgrade to SolarWinds Platform 2026.2.3 and above. If upgrade is not possible, use the workaround below:

1. Connect to the IPAM server.
2. Open Database Manager from the SolarWinds Platform folder of the start menu.
3. Select Add Orion Server, expand the SQL server in bold, right click the SolarWinds Platform database and select New Query.
4. Paste the query below and select Execute query:

-- Scripts are not supported under any SolarWinds support program or service.
-- Scripts are provided AS IS without warranty of any kind. SolarWinds further
-- disclaims all warranties including, without limitation, any implied warranties
-- of merchantability or of fitness for a particular purpose. The risk arising
-- out of the use or performance of the scripts and documentation stays with you.
-- In no event shall SolarWinds or anyone else involved in the creation,
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-- (including, without limitation, damages for loss of business profits, business
-- interruption, loss of business information, or other pecuniary loss) arising
-- out of the use of or inability to use the scripts or documentation.

DELETE FROM IPAM_Setting WHERE Name LIKE '%UiSetting.SubnetIpsColumn%' AND LEN(Value) >= 4000
ALTER TABLE IPAM_Setting
ALTER COLUMN [Value] nvarchar(MAX) NULL

Or remove Custom Properties to reduce the JSON data size.