SuiteCRM log file entries : [FATAL] Email address save error / IMAP Mailbox empty Issues / Upgrade from 7 to 8

I’ve been attemping to upgrade SuiteCRM from 7.13.1 to 8.2.2 in a local setup using XAMPP v8.2.0 unsuccessfully using the 8.2.3 upgrade from 7.13x upgrade file under the admin account. Each time I attempt to upload the file, I first perform a Repair and restart the
Apache and MySQL services. Also when editing a user acocunt, I receive a popup error “Exception occurred… Internal server error” after about 5 seconds.
The SuiteCRM error log file contains the following entries accordingly:
[FATAL] Email address save error
[FATAL] InboundEmail | Access denied.
[FATAL] Couldn’t connect to mail server id: dfcc17d2-b5fd-0cc6-74aa-63dd83c42b27

When editing the Inbound Email Account for this user and setting the SMTP account, the connection completes successfully. Yet when selecting the monitored folders which currently show Drafts,INBOX,Spam, the Select Subscribed folders popup box is empty.
When editing the SMTP owner account which is blank, I try to select the correct user but the field remains blank.

I’ve tried increasing the following to no avail:
max_execution_time
memory_limit
max_input_time

Help greatly appreciated with these issues.

My configuration is:

My.ini:
max_connections = 250
key_buffer_size = 4096M
max_allowed_packet = 3M
sort_buffer_size = 4096K
net_buffer_length = 32K
query_cache_limit = 256M
query_cache_size = 256M
table_open_cache=6000
table_cache=5000
thread_cache_size = 128
read_buffer_size = 4096K
read_rnd_buffer_size = 8096K
myisam_sort_buffer_size = 128M
thread_concurrency = 8
innodb_buffer_pool_size = 5096M
innodb_log_file_size=1274M
innodb_log_buffer_size=8M
innodb_flush_log_at_trx_commit=1
innodb_lock_wait_timeout=50
max_allowed_packet = 64M
key_buffer = 96M
sort_buffer_size = 96M
read_buffer = 18M
write_buffer = 12M
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 16M
write_buffer = 16M

PHP.ini:
display_errors = Off
error_reporting = E_ALL & ~E_DEPRECATED & ~E_STRICT
log_errors = On
output_buffering=4096
implicit_flush=Off
max_execution_time=796
max_input_time=8600
memory_limit=7168M
error_reporting=E_ALL & ~E_DEPRECATED & ~E_STRICT & ~E_NOTICE
display_errors=Off
display_startup_errors=On
log_errors=On
log_errors_max_len=1024
report_memleaks=On
auto_globals_jit=On
post_max_size=5012M
file_uploads=On
max_file_uploads=40
allow_url_fopen=On
allow_url_include=Off
default_socket_timeout=60
display_startup_errors=On
track_errors=Off
sql.safe_mode=Off

What should be these values?

I don’t usually configure those values for SuiteCRM, I just leave them with their defaults.