Hi @maxfabran,
if you have the error regarding AIOS firewall error: Class “AIOWPS\Firewall\Rule_Ban_Post_Blank_Headers” not found somehow the rule ban post blank related class not found some how.
If possible try upload the AIOS 5.2.5 again as AIOS 5.2.4 do not have this feature regarding ban post blank headers
last time old topic if you have this error and if it raises 500 error due that error some how that file do not have read permission and one of the reason it show that errror.
Do you can use the currently the AIOS plugin with that error? Let me know which AIOS version you have.
Solution I consider here is the export all settings , and then try update AIOS 5.2.5 latest by uploading all files to /wp-content/plugins/all-in-one-wp-security-and-firewall
Regards