A 400 error means the server could not understand the request. One possibility is that the amino acid sequence getting sent to the host is bogus somehow.

Submitted a support request even though the error seems to be on our side:

Hello!

My name is Ann Loraine, and I work at University of North Carolina at Charlotte where I am a Professor of Bioinformatics and Genomics.

I have been a many years user of the InterProScan services at EBI, which I really love

I am writing because an application my lab developed that uses the InterProScan REST API has been unable to "talk to" the service for a couple of days now. (Today is the second day we have noticed this problem.)

Would you be able to look into it and let us know what you find?

The application that is using the service is called ProtAnnot. It is an "App" for Integrated Genome Browser, described in this publication from a few years back: https://pubmed.ncbi.nlm.nih.gov/27153567/.

The error message we are seeing in our app looks like:

ERROR o.l.i.p.i.InterProscanServiceRest - Server returned HTTP response code: 400 for URL: http://www.ebi.ac.uk/Tools/services/rest/iprscan5/run
java.io.IOException: Server returned HTTP response code: 400 for URL: http://www.ebi.ac.uk/Tools/services/rest/iprscan5/run
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:2011)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1602)
at org.lorainelab.igb.protannot.interproscan.InterProscanServiceRest.readResponseFromPost(InterProscanServiceRest.java:163)
at org.lorainelab.igb.protannot.interproscan.InterProscanServiceRest.run(InterProscanServiceRest.java:178)
at org.lorainelab.igb.protannot.ProtAnnotService.loadSequence(ProtAnnotService.java:751)
at org.lorainelab.igb.protannot.ProtAnnotService$4.runInBackground(ProtAnnotService.java:583)
at org.lorainelab.igb.protannot.ProtAnnotService$4.runInBackground(ProtAnnotService.java:579)
at com.affymetrix.genometry.thread.CThreadWorker.doInBackground(CThreadWorker.java:73)
at java.desktop/javax.swing.SwingWorker$1.call(SwingWorker.java:305)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
at java.desktop/javax.swing.SwingWorker.run(SwingWorker.java:342)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
at java.base/java.lang.Thread.run(Thread.java:1583)

The most important line here is: "Server returned HTTP response code: 400 for URL: http://www.ebi.ac.uk/Tools/services/rest/iprscan5/run"

Has something about the API changed? Previous requests were working, so I'm wondering if maybe something about the API has changed to cause the problem.

Sincerely,

Ann Loraine, Ph.D.
University of North Carolina of Charlotte
Head of the IGB project

Update:

This Interpro Help page (https://www.ebi.ac.uk/interpro/help/) has a section named "Technical corner" with a link labeled "Programmatic access" that opens this page: https://github.com/ProteinsWebTeam/interpro7-api/tree/master/docs. However, the information is mainly related to retrieving information from the Interpro data store, not running InterproScan.

Another section on the same page is labeled "InterProScan" and contains a link labeled "Job Dispatcher documentation" that links to this page: https://www.ebi.ac.uk/jdispatcher/docs/. I think this is probably the documentation for the InterProScan job submission API, the thing that appears to be broken right now, either due to an error on the server side or a change in the API that ProtAnnot needs to be modified to accommodate.

We figured out that the problem seems to be using an email address (in the InterProScan database selection menu) that contains the string "test" anywhere in the domain name part of the user-entered email address.

Sent to support@ebi.ac.uk in reploy to their support ticket response:

Hello!

This is Ann Loraine again.

I think we figured out the problem.

It turns out that the person who was testing ProtAnnot was using this email address when submitting the InterProScan request:

test@test.com

For some reason, that email address was triggering the error.

I was curious about why that was causing a problem, so I tried a few other variations that included "test" in the domain name for the email address. It seems like the string "test" causes problems.

I hope this will be helpful.

I really appreciate having access to this service. Thank you again!

• Ann Loraine

and also we got back this:

<URL: http://helpdesk.ebi.ac.uk/Ticket/Display.html?id=820184 >

Dear Ann,

Thank you for your email, and sorry you're experiencing issues with the
InterProScan API. The REST API has changed, and submitting sequences
through the InterPro website
(https://www.ebi.ac.uk/interpro/search/sequence/) which uses the same
API still works.

An error 400 usually means incorrect data when submitting the query;
could you share the parameters used when submitting a job? Also, the API
response should include additional details on why the job failed to be
submitted.

Kind regards

On 2025-07-08 15:29, The RT System itself via RT wrote:
> Tue Jul 08 15:29:48 2025: Request 820184 was acted upon.
> Transaction: Queue changed from support to interhelp by RT_System
> Queue: interhelp
> Subject: InterproScan API not working at the moment
> Owner: Nobody
> Requestors: aloraine@gmail.com
> Status: new
> Ticket <URL: http://helpdesk.ebi.ac.uk/Ticket/Display.html?id=820184
> >
>
>
> This ticket has been moved to your queue by RT_System
> The original request:
>
> User's email address: aloraine@gmail.com
> Feedback topic: InterPro
> Referrer URL: https://www.ebi.ac.uk/interpro/help/
> User's IP address: 152.15.112.252
> Web browser used: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)
> AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36
> Message sent: Tuesday 8 July 2025 15:29
> Message content:
> ------------------------
>
> Hello!
>
> My name is Ann Loraine, and I work at University of North Carolina at
> Charlotte where I am a Professor of Bioinformatics and Genomics.
>
> I have been a many years user of the InterProScan services at EBI,
> which I really love
>
> I am writing because an application my lab developed that uses the
> InterProScan REST API has been unable to "talk to" the service for a
> couple of days now. (Today is the second day we have noticed this
> problem.)
>
> Would you be able to look into it and let us know what you find?
>
> The application that is using the service is called ProtAnnot. It is an
> "App" for Integrated Genome Browser, described in this publication from
> a few years back: https://pubmed.ncbi.nlm.nih.gov/27153567/.
>
> The error message we are seeing in our app looks like:
>
> ERROR o.l.i.p.i.InterProscanServiceRest - Server returned HTTP response
> code: 400 for URL:
> http://www.ebi.ac.uk/Tools/services/rest/iprscan5/run
> java.io.IOException: Server returned HTTP response code: 400 for URL:
> http://www.ebi.ac.uk/Tools/services/rest/iprscan5/run
> at
> java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:2011)
> at
> java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1602)
> at
> org.lorainelab.igb.protannot.interproscan.InterProscanServiceRest.readResponseFromPost(InterProscanServiceRest.java:163)
> at
> org.lorainelab.igb.protannot.interproscan.InterProscanServiceRest.run(InterProscanServiceRest.java:178)
> at
> org.lorainelab.igb.protannot.ProtAnnotService.loadSequence(ProtAnnotService.java:751)
> at
> org.lorainelab.igb.protannot.ProtAnnotService$4.runInBackground(ProtAnnotService.java:583)
> at
> org.lorainelab.igb.protannot.ProtAnnotService$4.runInBackground(ProtAnnotService.java:579)
> at
> com.affymetrix.genometry.thread.CThreadWorker.doInBackground(CThreadWorker.java:73)
> at java.desktop/javax.swing.SwingWorker$1.call(SwingWorker.java:305)
> at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
> at java.desktop/javax.swing.SwingWorker.run(SwingWorker.java:342)
> at
> java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
> at
> java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
> at java.base/java.lang.Thread.run(Thread.java:1583)
>
> The most important line here is: "Server returned HTTP response code:
> 400 for URL: http://www.ebi.ac.uk/Tools/services/rest/iprscan5/run"
>
> Has something about the API changed? Previous requests were working, so
> I'm wondering if maybe something about the API has changed to cause the
> problem.
>
> Sincerely,
>
> Ann Loraine, Ph.D.
> University of North Carolina of Charlotte
> Head of the IGB project

–
Matthias Blum
InterPro/Pfam Development Project Leader
Sequence Family Resources
European Bioinformatics Institute (EMBL-EBI)