scheme view stuck with loading animation

[JW]

After a few click between schemes, the scheme is stuck with loading animation.

refresh this url will not resume
xxx.com/scada/View.aspx?viewID=21
refresh thi url will resume
xxx.com/scada

screen cap
https://drive.google.com/file/d/12usW761By5bdMw2ZGQ4fD4Y1J-GB6wOy/view?usp=sharing

web log

2021-03-29 11:39:11 <os-server><www-data><ACT> Request SCADA-Server state
2021-03-29 11:39:11 <os-server><www-data><ERR> Incorrect SCADA-Server response to state request
2021-03-29 11:39:11 <os-server><www-data><ACT> Disconnect from SCADA-Server
2021-03-29 11:39:11 <os-server><www-data><ACT> Connect to SCADA-Server "localhost"
2021-03-29 11:40:12 <os-server><www-data><ACT> Request SCADA-Server state
2021-03-29 11:40:12 <os-server><www-data><ERR> Incorrect SCADA-Server response to state request
2021-03-29 11:40:12 <os-server><www-data><ACT> Disconnect from SCADA-Server
2021-03-29 11:40:12 <os-server><www-data><ACT> Connect to SCADA-Server "localhost"
2021-03-29 11:44:05 <os-server><www-data><ACT> Request SCADA-Server state
2021-03-29 11:47:49 <os-server><www-data><ACT> Request SCADA-Server state
2021-03-29 11:48:38 <os-server><www-data><ACT> Logout: user. IP address: 127.0.0.1
2021-03-29 11:48:42 <os-server><www-data><ACT> Request SCADA-Server state
2021-03-29 11:48:42 <os-server><www-data><ACT> Login: user (Guest). IP address: 127.0.0.1
2021-03-29 11:48:42 <os-server><www-data><ACT> User information has been updated. IP address: 127.0.0.1. Session: EE06B64156E60F769A17C026
2021-03-29 11:48:42 <os-server><www-data><ACT> Retrieve components from the installed plugins

server log

2021-03-29 11:38:43 <os-server><root><ACT> Disconnect client 127.0.0.1
2021-03-29 11:39:11 <os-server><root><ACT> Connect to client 127.0.0.1
2021-03-29 11:39:11 <os-server><root><ACT> The user ScadaWeb is successfully authenticated
2021-03-29 11:40:11 <os-server><root><ACT> Disconnect client 127.0.0.1
2021-03-29 11:40:12 <os-server><root><ACT> Connect to client 127.0.0.1
2021-03-29 11:40:12 <os-server><root><ACT> The user ScadaWeb is successfully authenticated
2021-03-29 11:48:42 <os-server><root><ACT> Check username and password for user. Result: passed

[JW]

After brief test, seems only happens when using Firefox. But not 100% sure at the moment.

[JW]

The issue can be reproduce on the official demo website.
http://rapidscada.net/scada/Login.aspx
Use Firefox
Click “Home scheme” and “Server room scheme” repeat a few times

screen cap
https://drive.google.com/file/d/1WrJHLx8mlKARNsTVEk-HH14z4gVD7aad/view?usp=sharing

[Mikhail]

Yes, the issue is reproduced. But demo server has very low CPU and RAM.
What are the parameters of your server? Is it Linux or Windows?

[JW]

I tried on 3 of my servers, both are Linux
1. 2 core cpu + 1GB ram (+2gb ssd swap)
2. 4 core 8th gen i5 + 8GB ram

The issue appear on both while I am using Firefox from my laptop within 1~3 minute of clicking.
I tried Chrome, after clicking about 10 minutes, they are still working.

[JW]

I did another test on my laptop as server
Windows 10, i5 + 16GB RAM

Using Firefox both locally and remotely will have this issue.

There is an error on Firefox when stuck on loading.
ns_error_not_initialized schemeform.js

https://drive.google.com/file/d/1I-vHlothMHODKWG7C_nNVINvF_xL367a/view?usp=sharing

[Mikhail]

This issue is interesting and unusual. Considering the fact that we anyway will rewrite the entire web application, I suppose, we should check the new web app if this issue still occurs and then fix it.
dotNET5 doesn’t support WebForms technology that is currently used that’s why we have to create the web app from scratch.

[Author]

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