Non si aggiornano i plugin

Buongiorno a tutti,
quando cerco di aggiornare i plugin mi esce questo errore:
Aggiornamento fallito: 500 Internal Server Error <!--[if lte IE 6]><![endif]--> Internal Server Error The server encountered an internal error or misconfiguration and was unable to complete your request. Please contact the server administrator to inform of the time the error occurred and of anything you might have done that may have caused the error. More information about this error may be available in the server error log. Web Server at lamorosina.it <!-- - Unfortunately, Microsoft has added a clever new - "feature" to Internet Explorer. If the text of - an error's message is "too small", specifically - less than 512 bytes, Internet Explorer returns - its own error message. You can turn that off, - but it's pretty tricky to find switch called - "smart error messages". That means, of course, - that short error messages are censored by default. - IIS always returns error messages that are long - enough to make Internet Explorer happy. The - workaround is pretty simple: pad the error - message with a big comment like this to push it - over the five hundred and twelve bytes minimum. - Of course, that's exactly what you're reading - right now. -->

Poi nella root mi scrive il files che allego e l’home page sparisce e mi viene questo messaggio (Briefly unavailable for scheduled maintenance. Check back in a minute.) e non va via più fino a quando non rimuovo il file .maintenance con questo codice (<?php $upgrading = 1489701517; ?>).

Cosa posso fare?

Grazie