Hello! 
We are experiencing big problems with a .NET application that we are using to print labels using browserprint. 

We shipped this application in june 2024 and it was working great in the start then we added more users and problems with printing began. 

What is happening is that the application works great until it suddenly stops and nothing happens when we try to print out using our application or any other browserprint application the only solution is to restart the printer after a restart it is working a while until the problem comes back. Other application are still working and we can print from these without problem but all applications that are using browserprint and printing from USB are not working. 

We do not really know how to get past this we are not able to replicate this in our printer but it happens "out in the wild". 

What we have tried to do is following:

• Rewrote the code removing all status requests where we asked for the status of the printer etc. 
• Removed timer from USB-port (windows can sometimes make the printer sleep)
• Changed timeout settings in the printer (timeout for internal wired)
• Changed ZPL-format from sending two zplcommands one with setting to one. 

We are only using USB-connected printers the models that we are using is GX420t and ZD421 user are using desktop computers with the same installation of zebra browser print. 

Any tips on what we can do to find out what is happening? 

I will attach our JS code and zpl-samples in the attached files.