Client Access License files upload not working

When we want to upload the Client Access License files on our 6.0.3 server. We get the following exception in the client:
CRJAZ1490E: The upload did not complete in a reasonable amount of time; the server may be unavailable
The server is running on Websphere Application server. (not liberty)
It is showing high CPU consumption and the following message occurs in the logs:
WSVR0605W: Thread "WebContainer : 1 @@ 15:38 <Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0@0:0:0:0:0:0:0:1> /jts/service/com.ibm.team.repository.service.internal.license.ILicenseUploadService" (00000132) has been active for 683036 milliseconds and may be hung. There is/are 1 thread(s) in total in the server that may be hung.
at java.io.InputStream.read(InputStream.java:182)
at javax.mail.internet.MimeBodyPart.<init>(MimeBodyPart.java:85)
at javax.mail.internet.MimeMultipart.parse(MimeMultipart.java:177)
at javax.mail.internet.MimeMultipart.getCount(MimeMultipart.java:104)
at com.ibm.team.repository.service.internal.license.AbstractLicenseUploadService.findFormInput(AbstractLicenseUploadService.java:128)
at com.ibm.team.repository.service.internal.license.AbstractLicenseUploadService.parseAndProcess(AbstractLicenseUploadService.java:259)
at com.ibm.team.repository.service.internal.license.AbstractLicenseUploadService.perform_POST(AbstractLicenseUploadService.java:107)
at com.ibm.team.repository.service.TeamRawService.service(TeamRawService.java:92)
What could be the issue