AlanH

I have been trying various settings and have set Mailstore as a trusted application with only the ‘Do not scan encrypted traffic’ exclusion enabled and that now works. This seems like a viable solution to the issue - are there any disadvantages to doing this?

The error Mailstore throws is as in my first message. I have been told that the "Accept all certificates” option is not something that is applicable because it’s not an option on Mailstore Home/Gmail. The Report Error… link leads to a page of diagnostic information but not sure it’s of much use to you (personal information redacted): The SSL/TLS certificate verification failed. In order to skip the certificate verification, please enable the "Accept all certificates" option. Details: Unable to perform revocation check of the server certificate. *** Environment *** Product Name: MailStore Home Product Version: 13.0.3.20071 App Build Date: 2020-09-07 App Copyright: Copyright (c) 2005-2020 MailStore Software GmbH App Description: App Dir: C:\Program Files (x86)\MailStore\MailStore Home App File Name: C:\Program Files (x86)\MailStore\MailStore Home\MailStoreHome.exe App Title: MailStore Operating System: Windows 10 Home x64 OS Bitness: x64 Process Bitness: x86 Is Mono: False Is Windows: True .NET 4 Release Key: 528372 .NET CLR Version: 4.0.30319.42000 Proc Culture: en-GB Proc UI Culture: en-GB Machine Name: DESKTOP-xxxxx User Domain Name: DESKTOP-xxxxx User Name: xxxxxx License ID: xxxxxxxxxxxxxxxxxx *** Exception Details *** #DG.#yI: The SSL/TLS certificate verification failed. In order to skip the certificate verification, please enable the "Accept all certificates" option. Details: Unable to perform revocation check of the server certificate. Server stack trace: at #DG.#lN.#4Ke(String #wm, Char #g, String #3bb, PropertySet #4bb, Boolean #wQf) at #9t.#qD.#6yl(#RI #pTm) at MailStore.Common.Progress.ProgressDialog.#6I() at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Object[]& outArgs) at System.Runtime.Remoting.Messaging.StackBuilderSink.AsyncProcessMessage(IMessage msg, IMessageSink replySink) Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.EndInvokeHelper(Message reqMsg, Boolean bProxyCase) at System.Runtime.Remoting.Proxies.RemotingProxy.Invoke(Object NotUsed, MessageData& msgData) at System.Action.EndInvoke(IAsyncResult result) at MailStore.Common.Progress.ProgressDialog.#5I(IWin32Window #yk, String #qOf, #VX #tK, ProgressDialogMethod #RY) at #9t.#qD.#cJk() at #9t.#qD.#yKe() *** Server Exception Info *** Rebex.Net.TlsException: Unable to perform revocation check of the server certificate. at Rebex.Net.Imap.TryUpgrade(TlsParameters parameters, Boolean failOnClosed) at Rebex.Net.Imap.ConnectSync(String serverName, Int32 serverPort, TlsParameters parameters, SslMode security) at Rebex.Net.Imap.ConnectInternal(String serverName, Int32 serverPort, TlsParameters parameters, SslMode security) at #UAb.#1rg.#Trg() at #UAb.#1rg..ctor(String #en, Int32 #V9, String #gQf, Int32 #0Fb, ICertificateVerifier #b4n, #29g #Tlf, #tG #c4n, #8lg #p3n) at MailStore.Connectors.Mailboxes.ImapMailbox..ctor(String serverName, Int32 port, String protocol, Int32 timeout, ICertificateVerifier certificateVerifier, #eah mailboxType, #29g authentication, Boolean writeConnectionDebugLog, #8lg connectionMonitor, #Lpg mailboxCache) at #UAb.#hHb.#dHb(#SEb #cXb) at #UAb.#hHb.#1Gb(#SEb #cXb) at #lFb.#sFb.#rFb() at MailStore.ServiceFoundation.MailStoreServiceFoundation.#TSe(#9Qe #Rmc, String #wm, Char #g, String #3bb, PropertySet #4bb, Boolean #wQf) at #DG.#7Qe.#4Ke(String #wm, Char #g, String #3bb, PropertySet #4bb, Boolean #wQf) at #DG.#mN.Invoke(#BL #KQf, String #RY, BinaryReader #wW, BinaryWriter #7P) *** Inner Exception *** Rebex.Net.TlsException: Unable to perform revocation check of the server certificate. at Rebex.Net.TlsBaseSync.Process() at Rebex.Net.TlsBaseSync.Negotiate() at Rebex.Net.Tls12SocketSync.Negotiate() at Rebex.Net.TlsSocket.Negotiate() at Rebex.Net.ImapSocket.Upgrade(TlsParameters parameters) at Rebex.Net.Imap.TryUpgrade(TlsParameters parameters, Boolean failOnClosed) *** Inner Exception *** Rebex.Net.TlsException: Unable to perform revocation check of the server certificate. at Rebex.Net.TlsHandshakeSync.VerifyCertificate(String commonName, CertificateChain certificate) at Rebex.Net.TlsHandshakeSync.OnHandshakeReceivedClient(Byte[] buffer, Int32 offset, Int32 count, Handshake h) at Rebex.Net.TlsHandshakeSync.OnHandshakeReceived(Byte[] buffer, Int32 offset, Int32 count) at Rebex.Net.TlsBaseSync.ProcessHandshake(Byte[] buffer, Int32 offset, Int32 length) at Rebex.Net.TlsBaseSync.Process()

Thanks again, Berny. I added gmail.com as an exclusion but I get the same error. I also tried imap.gmail.com (which is the mail server) and that also gives the same error. Any other suggestions?

Thanks for the quick reply, Berny. Just tried that and it allows Mailstore to work. After Mailstore stared checking for emails, I switched Kaspersky back to “Scan encrypted connections upon request from protection components” and Mailstore kept on running so I assume it only checks just at the start. However, disabling the scan of encrypted connections isn’t a long-term fix as it disables too many other services. Can I add gmail.com as an exclusion?

I use Mailstore Home to backup my Gmail account but it stopped working last month, giving the following error, preventing it accessing my Gmail account: An error has occurred. The SSL/TLS certificate verification failed. In order to skip the certificate verification, please enable the "Accept all certificates” option. Details: Unable to perform revocation check of the server certificate. If I pause Kaspersky, it works correctly, so it looks like Kaspersky is blocking access for some reason. (The Mailstore Home error message isn’t quite correct as there is no "Accept all certificates” option. Is there a setting in Kaspersky that I can change to fix this? I’m running Kaspersky Internet Security 21.2.16.590 (b)