can't install any wp plugins

We recently moved WP hosts.

We backed up WP and imported it to a development site wp.mysite.com to get it all set up.

Once everything was done, we switched the DNS and went live with newdomain.com on the new server. It's been running for a while but I now see a problem with plug-ins. The end user wanted to add a plugin but gets a 403 permissions denied error and at the top of the error it lists wp.mysite.com (the old development site URL). So as it stands we cannot add any plug-ins.

I downloaded the entire database in SQL text and searched but couldn't find any references to wp.mysite.com.

My assumption is that the permalink hash does not match the permalinks (which appear correct).

I've went to Settings Permalinks and saved but they did not correct. Could this be corrected with a RewriteRule in .htaccess where wp.mysite.com gets redirected to newsite.com?

Is there a better way to correct the permalink hash?