"MultiTerm is unable to add the entry" error in SDL Trados Studio 2017

Hello,

 

in addition to my previous issue https://community.sdl.com/product-groups/translationproductivity/f/90/t/17880, I had a new error message "MultiTerm is unable to add the entry":  . This appears only with certain terms. For example I just wanted to add "indeks AWD" -> "index AWD" to the term base.

The error details are available from here: 

<SDLErrorDetails time="5/1/2018 2:43:38 PM">
  <ErrorMessage>MultiTerm is unable to add the entry.</ErrorMessage>
  <Exception>
    <Type>System.Runtime.InteropServices.COMException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</Type>
    <ErrorCode>-2147220961</ErrorCode>
    <HelpLink />
    <Source>MtTermbase</Source>
    <HResult>-2147220961</HResult>
    <StackTrace><![CDATA[   at Sdl.MultiTerm.TMO.Interop.EntriesClass.New(String EntryXML, Boolean Incomplete)
   at Sdl.MultiTerm.Client.UI.Viewer.ScriptingHost.SaveEntry(String content)]]></StackTrace>
  </Exception>
  <Environment>
    <ProductName>SDL Trados Studio</ProductName>
    <ProductVersion>14.0.0.0</ProductVersion>
    <EntryAssemblyFileVersion>14.0.5889.5</EntryAssemblyFileVersion>
    <OperatingSystem>Microsoft Windows 10 Pro</OperatingSystem>
    <ServicePack>NULL</ServicePack>
    <OperatingSystemLanguage>1033</OperatingSystemLanguage>
    <CodePage>1257</CodePage>
    <LoggedOnUser>MAEMEES\olav</LoggedOnUser>
    <DotNetFrameWork>4.0.30319.42000</DotNetFrameWork>
    <ComputerName>MAEMEES</ComputerName>
    <ConnectedToNetwork>True</ConnectedToNetwork>
    <PhysicalMemory>16202708 MB</PhysicalMemory>
  </Environment>
</SDLErrorDetails>

If I click "OK" or close this pop-up, it re-appears automatically. Only forced exit of SDL Trados Studio 2017 via Task Manager helps me to remove this pop-up. If I click "Enter" very fast after I have clicked "OK or close" on the pop-up, a message from the website:   (Teade veebilehelt is "Message from the website") appears.

From digging in the internet, I have read that this is related with update of Java/.NET Framework versions and/or with merging different term bases.

Can someone help me to figure out why this error appears?