i am close to the end of a Citect 2018 to Plant SCADA 2020r2 upgrade. all clients have been upgraded to 2020R2 update 31 and primary server the same . secondary server still on 2018 update 37 and on duty for last few weeks and all clients running without issue.
yesterday i shutdown the secondary 2018 server placing the 2020 Primary on duty and system was fine except for 1 Client machine which cannot establish coms to the primary? both are 2020r2 ? when the secondary was duty server (2018) it was ok. i get the following error
what do i look for. i checked configurator and all seems fine, it only failed comms since the duty server changed to 2020R2 ? and only on 1 client all 7 others are fine?
