OPC-UA "waiting_for

A customer has and issue connecting to a OPC-UA server provided by a MLC.

The setup
WebIQ 2.12.1
MLC14V20

WebIQ (pc based licese) <-> MLC
IO Handle configured and receiving "waiting for recconnect" message.

Testing so far:
UA client successfully connected to MLC OPC-UA server endpoint
WebIQ successfully connected to "opc.tcp://opcua.webiq.de:48010/WebIQ/DemoServer"
configure a IO Handle at an incorrect address, he receives different behaviour -> cycle between "connecting" & "waiting for reconnect"

So it looks like both server and client is working, just not with each other.
It appears as if WebIQ is being blocked in some way or is waiting for approval from the server.

Note: I've seen in another forum post that someone experience a similar issue and resolved it by reinstalling WebIQ Designer. However I would prefer to find a root cause before resorting to this.

***update***

After obtaining the connect.log, we were able to see a BadCertificateValidation error.
Common error when the date and time is not the same on both server and client. The customer corrected the date and time on their MLC and WebIQ was able to connect successfully, but this only lasted ~6 hours after which we receive the same error.

The MLC date and time are correct so now even though we are using a non-secure connection, we check the rejected and trusted certs on the server. Here we find after a cert is trusted, it will re-appear as rejected. We noticed some of the folders here are dated 2042...(both systems are dated correctly, so it's unclear why)
The all certs were cleared from MLC, still nothing.

Now all certs cleared from C:\programData\WebIQ\io-shared\ (some certs here were also dated 2042), now the customer has a working system.

OPC-UA "waiting_for_recconnect"