I probably don't use same Communication script. Anyway, there is same Delay/Wait algorithm using "Timer". So I'm dealing with same issue.
I have app that reads values from device on COM port every 15 seconds. And after last read before midnight it reports:
"COM Error: Error (-1): CommOpen - Port in use."
QuoteDisplay More22.1.22 23:59:46 COM Error: Error (-1): CommOpen - Port in use.
22.1.22 23:59:47 COM Error: Error (-1): CommOpen - Port in use.
22.1.22 23:59:47 COM Error: Error (-1): CommOpen - Port in use.
22.1.22 23:59:48 COM Error: Error (-1): CommOpen - Port in use.
22.1.22 23:59:49 COM Error: Error (-1): CommOpen - Port in use.
22.1.22 23:59:50 COM Error: Error (-1): CommOpen - Port in use.
22.1.22 23:59:50 COM Error: Error (-1): CommOpen - Port in use.
22.1.22 23:59:51 COM Error: Error (-1): CommOpen - Port in use.
22.1.22 23:59:52 COM Error: Error (-1): CommOpen - Port in use.
22.1.22 23:59:53 COM Error: Error (-1): CommOpen - Port in use.
22.1.22 23:59:53 COM Error: Error (-1): CommOpen - Port in use.