Most likely, engineering user rights are not defined (default is admin / rw).
Most likely, the web browser saved the files to memory. Try one of these options, try the keyboard shortcut "Ctrl + F5", use an anonymous web browser window, or view the web definition in another web browser.
Most likely, the web definition is displayed on the PLC by the FreeRTOS operating system, which displays only one font on the web.
This is probably a UTF-8 encoding completion error. This bug can be resolved by playing RT at version 2.4.0.18 and higher.
Most likely, the user will not have the time on the web server from which you are trying to set the write / read rights assigned to the function. In your PLC manager report, in the "User rights for HMI" tab, check whether the user under which you access the web server has the specific rights defined here.
Make sure the web server template is selected in the PLC properties in your report.
If the webserver is running on a PLC with the FreeRTOS operating system, this is a feature where it is not and will not be implemented.
For PLCs running Linux, reading history on the web is supported, check the following:
The minimum guaranteed number of records that can be stored in the history on one PLC is specified in the catalog sheet of each PLC in the "Programming" section.
There is no way to increase the number of user views. When the maximum number of records is exceeded, the oldest record will be overwritten.
On the PLC operating system FreeRTOS it is not possible resp. there is an option in the PLC properties, but after disabling the site to upload the configuration, the change will not be overwritten. On a Linux operating system PLC, this is implemented, just disable the website in the PLC properties and upload the configuration to the PLC.
This is because the definition was created in a resolution for the HT200 terminal. On the web, select "Fit to screen" for the resolution.
Use "Ctrl + left-click" to select the objects you want to display.
It is not possible to change the port number for the web server on the FreeRTOS PLC. For PLC operating systems Linux, a port number for the web server is possible. The change must be made in the vIDE in the PLC properties (upload the configuration to the PLC) and also in the Linux directory via SSH under the path etc / rules / Firewall / Rules.