I've now found out how to increase the PHP memory limit by adding a line to the .ini.php file

memory_limit = 256M

But now I'm getting this error message:

500 Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator at webmaster@this.domain to inform them of the time this error occurred, and the actions you performed just before this error.

More information about this error may be available in the server error log.

As suggested by the error message, you should check the PHP error log.

Its location depends on your setup.

You may try with this shell command:

php --info | grep ^error_log

but please be aware that the error log of the PHP shell and the error log of the web server may be different.

Hi this is the contains of the error_log file

[2018-11-28 10:07:10] [core:error] [client 51.7.82.213:0] End of script output before headers: php71-cgi, refererhttps://www.psldrive.co.uk/index.php/dashboard/system/update/update...
[2018-11-28 10:11:33] [core:error] [client 51.7.82.213:0] End of script output before headers: php71-cgi, refererhttps://www.psldrive.co.uk/index.php/dashboard/system/update/update...
[2018-11-28 10:14:29] [core:error] [client 51.7.82.213:0] End of script output before headers: php71-cgi, refererhttps://www.psldrive.co.uk/index.php/dashboard/system/update/update...

Does that mean anything to you? My hosting service are rubbish and they won't assist me in anyway. I'm going to look into moving my site next week.

These are my PHP settings:

# PHP Settings
max_execution_time - 120
log_errors_max_len - 1024
max_file_uploads - 20
max_input_nesting_level - 64
max_input_time - 120
max_input_vars - 1000
memory_limit - 256M
post_max_size - 128M
sql.safe_mode - Off
upload_max_filesize - 128M
ldap.max_links - 16
mysqli.max_links - 16
mysqli.max_persistent - Unlimited
odbc.max_links - 16
odbc.max_persistent - Unlimited
pcre.backtrack_limit - 1000000
pcre.recursion_limit - 100000
pgsql.max_links - 16
pgsql.max_persistent - Unlimited
session.cache_limiter - <i>no value</i>
session.gc_maxlifetime - 7200
soap.wsdl_cache_limit - 5
$_SERVER['rate_limit'] - 12500
$_SERVER['REDIRECT_rate_limit'] - 12500

I've transferred my website to a new host (SiteGround) and all my problems have disappeared.

Thank goodness....

It must have been my previous host (names.co.uk) - They were totally unwilling to help me and obviously the issues where on their servers.

Thanks for your help.