503 errors with custom visuals with report server using form authentication

[lsteffens]

Hi.

In the last 2 months I have problems with using custom visuals (of the marketplace) in PBI reports on my report server using custom authentation (I use Forms authentication).

The 503 error is quite random and might not happen everytime, but can be reproduced by hitting F5 in the browser.

Sometimes all custom visual are ommited, sometimes only a part of the custom visuals are drawn - sometimes a scrollbar is shown on the custom visual, but there should be no scrollbar (e.g. the tag cloud visual).

It's a very random error/problem.

Here is a small example from the Edge console window:

GET https://my.server.com/powerbi/libs/scripts/customVisualsHost.bundle.js net::ERR_ABORTED 503
cvSandboxMinimal.htm:16 GET https://my.server.com/powerbi/libs/scripts/visualSandbox.minimal.externals.js net::ERR_ABORTED 503
cvSandboxMinimal.htm?=&plugin=tagCloud8448D0BE3AE3424D97B3973515418218&locale=de-DE:17 GET https://my.server.com/powerbi/libs/scripts/customVisualsHost.bundle.js net::ERR_ABORTED 503
cvSandboxMinimal.htm?=&plugin=tagCloud8448D0BE3AE3424D97B3973515418218&locale=de-DE:7 GET https://my.server.com/powerbi/libs/styles/visualsandbox.css net::ERR_ABORTED 503
cvSandboxMinimal.htm?=&plugin=tagCloud8448D0BE3AE3424D97B3973515418218&locale=de-DE:16 GET https://my.server.com/powerbi/libs/scripts/visualSandbox.minimal.externals.js net::ERR_ABORTED 503
cvSandboxMinimal.htm?=&plugin=htmlContent443BE3AD55E043BF878BED274D3A6855&locale=de-DE:7 GET https://my.server.com/powerbi/libs/styles/visualsandbox.css net::ERR_ABORTED 503

The problem happens on all major browser in their current version.

The Report Server runs the January 2021 release, but the problem showed up with the release before (October 2020 - most current version), too.

Has anybody seen this odd behavior - and is there a solution/workaround for this 503 problem?

Thanks,

Lars

[V-pazhen-msft]

@lsteffens 
503 error is indicating that a server is temporarily unable to handle the request. This may be due to the server being overloaded or down for maintenance. I will suggest you to check the log files first: C: \ Program Files \ Microsoft Power BI Report Server \ PBIRS \ LogFiles

Since you are using custom visuals this could cause fluctuation in connection, and there is one limitation you should be aware of. If the custom visuals using an API version that is greater than the one that was released with PBIRS then it won't work properly. 

Paul Zheng _ Community Support Team
If this post helps, please Accept it as the solution to help the other members find it more quickly.

[lsteffens]

Thanks for your answer.

I (re)checked the logs but they show to indication of errors.

But the RSPowerBI*.log file is not a joy to read as there are many long DAX expressions in it that are not comming from by DAX code in the reports.

As "Sandbox" is in the text before the long DAX expressions, maybe they are part of what custom visuals do internally with DAX - I don't know ...

The custom visuals are the most current versions downloaded of the marketplace from the most recent PBI Desktop for my report server. So there should be not problem with them (?).

I use the custom visuals "Text Filter", "Tag Cloud" and "Text Enhancer" - and very seldomly "Html Content", btw...

Where do check the API version of a downloaded custom visual? I can only see the version number of the visual itself in the infobox of it.

Do you have any further suggestions or hints?

Thanks.

[emourits]

Did you ever resolve this issue? We are experiencing exactly the same problem, also with custom forms authentication.

[lsteffens]

Even after many updates to Power BI Reportserver to the most current version (Mai 2023), this problem persists.

I try to avoid all custom visuals and the one and only custom visual I use in my reports for now is "Text Filter" (why is there no build in visual in PBI ^^).

It sometimes disappears, but after switching a tab in the PBI report and switching back it appears again (sometimes not ...).

I'm currently trying to integrate some D3.js with the corresponding custom visual to give my reports an extra touch, and the problem is back again.

Currently Firefox seams to have no problems with custom visuals .... but Edge and Chrome have.

Maybe it has something to do with how complex the report page is - more non custom visuals on the same reportpage makes the problem worse.

So if someone has a clue what's going on ... just drop your 2 cents here 😉

[d_gosbell]

I have not seen this with the default windows authentication, so it could be an issue with your custom authentication provider. Have you tried debugging that? Have you implemented exception logging in your code?

[lsteffens]

Thanks for your reply.

I'm using the code from github for SQL Server 2017 (this is the most current version of the sample) (https://github.com/Microsoft/Reporting-Services/tree/master/CustomSecuritySample), with minor changes in order to correctly verify the user and password against encrypted password stored on SQL Server coming from IIS forms/custom authentication template.

I'll try to implement some kind of logging inside the custom security code for RS or, maybe better, hook the VS debugger on to the DLLs/processes (if that is even possible - I have not done that before).

But I think it's some kind of configuration problem with PBIRS website - maybe a timeout.

The problem with disappearing custom visuals seems to get worse if the report page is more complex and PBI and the browser has more work to do. (Firefox seems to work for now)

Anyway, if I have some "news" I'll post it here ....

Thanks again!