I am not aware of any problems deleted subscribers. We have tested that quite a bit. If you’re having trouble we should probably look at what plug-ins, etc. you have in your system.
Please click the following link for instructions on what info to provide support. If posting to the forum, please do not include your URL.
https://sendpress.com/support/knowledgebase/what-information-should-i-provide-in-a-support-ticket/
We can take a look and see if anything jumps out at us. It’s also helpful if you can take a look at your Apache server logs. Most times, if there is an error, it will show up in the error logs and should pinpoint the problem.