Among several live sites that are working fine with MainWP, I also have two sites under development that have MainWP installed.
Both sites have the same theme, same plugin stack, same host, same server. One of those sites cruises along perfectly. The other one returns a “…not returning expected HTTP request response” email every day. The email says the site is returning a “404 - Not Found” response.
This is odd because, although the site is under development, it is easily accessible - WordPress admin, etc…
The other site that is under development is apparently returning a “200” as it should.
Both sites use the CMP - Coming Soon and Maintenance plugin, as do six other live sites. For both of the development sites, the CMP plugin is set to return a “200 HTTP OK” response. As I mentioned earlier, MainWP gets a 404 on one and apparently as 200 on the other.
Oddly enough, any plugin/theme updates that MainWP picks up on run fine on both sites - even the one with the 404 response.
Is there anything about MainWP that could cause this issue?
Just to provide an update on this - the issue was caused because the URLs for the WordPress Address and Site Address on the WP Admin > Settings > General page were http:// when in fact, the site was using https://.
After WordPress Address and Site Address were changed to https://, the issue was resolved.