Bug when syncing CalDAV / CardDAV

I host my own domains using cPanel.

For over a month, I have been trying to find a rogue app on prem that was flagging my own IP as suspect.

After all this time, I have narrowed the issue down to eMClient

When setting up eMClient to work with an IMAP account that also has CalDAV/CardDAV services, I have setup the account twice - one IMAP and one for the Calendar and Contacts (same username, same password)

The URL I point to for the server is: https://mydomain.com:2080/calendars/[email protected]

Which works a treat (once). When I save the settings, eMClient changing the link to https://mydomain.com:2080/calendars/[email protected]/ - that additional “/” seems to error out the link and subsequently manifest itself as a failed logon attempt which ultimately results in a blocked IP address on the firewall at my Hosting provider. I am not sure if this is a bug with eMClient or cPanel, but as I can use apps like Thunderbird without issue, I have stopped the eMClient use until a solution can be identified.

Please advise.