Hi @Issif,
Welcome to the 
community support forums !!
We are excited that you joined our OSS community. Please read about some of the FAQs in the community 
I do not have knowledge of Oncall but I just saw the release notes on GitHub there seems to a new version v1.2.19.
What I would suggest is to try to use this new version and if you still having issues, then would appreciate it if you can open a bug report about this in our official GitHub repository using this link.
Provide all the information (you can simply copy/paste your data + screenshot from here to there).
Lastly, paste the link to your GitHub issue here in this post so that all other community users can also track it. I will also add more additional information to it 